[HN Gopher] Adventures of putting 16 GB RAM in a motherboard tha...
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Adventures of putting 16 GB RAM in a motherboard that doesn't
support it (2019)
Author : walterbell
Score : 395 points
Date : 2021-12-13 02:35 UTC (20 hours ago)
(HTM) web link (www.downtowndougbrown.com)
(TXT) w3m dump (www.downtowndougbrown.com)
| bell-cot wrote:
| My n=1 - A Dell system, "16GB max memory" (Dell) vs. "32GB max
| memory" (web sites of some leading 3rd-party memory
| manufacturers). The latter seem to be correct. Both Windows 10
| and the hardware self-tests in the Dell's BIOS fully support the
| extra memory.
| fuzzfactor wrote:
| I've got an old HP business tower that only officially supports
| 4GB of DDR2 and has 4 slots.
|
| Works just fine on 800MHz using 4GB total.
|
| Needed to use 667MHz DIMMS so it would handle 8GB.
|
| Almost worked with 800 but was unstable.
| asdff wrote:
| I still use a 2012 macbook, which was the last one where Apple
| graciously let you replace most of the parts including the RAM
| sticks yourself before soldering them to the logic board.
| According to official documentation this computer could have only
| been ordered with 2x2gb sticks, can only support an upgrade up to
| 2x4gb sticks, but here I am running 2x8gb sticks without having
| to do any fiddling, just plug and play. Unlike OP though, windows
| 10 over bootcamp is luckily able to pick up the 16gb just fine
| somehow.
| charwalker wrote:
| I've run 16gb in mine alongside that little dual core CPU. It
| works better than it did in 2012 thanks to a 60gb SSD too.
| grishka wrote:
| I do wonder if that Mac Mini from 2011 I have but haven't used
| in a long time also secretly supports 16 GB. I upgraded it to 8
| GB ages ago and the docs said that's as far as it goes.
| NaOH wrote:
| Look up the mid-2011 Mac mini models on EveryMac.com and it
| states that 16GB is supported in 2 x 8GB configurations.
| oso2k wrote:
| I use my 2011 Mac Mini with 16GB. Been running it that way
| nearly since the day I bought it. It's on its 3rd HD, a 120GB
| SSD. Wikipedia article mentioned it would work with 16GB so I
| upgraded it as soon as I could.
| kelnos wrote:
| Funny timing: I just upgraded a 2011 Mac Mini from 4GB to
| 16GB _yesterday_ , and it works just fine. After searching
| around, I found a site (can't remember the name) where they
| specifically call out that the _actual_ amount of RAM that
| various Macs support, regardless of what Apple 's official
| specs say.
|
| (Had to crack it open because the old spinning-rust hard
| drive was starting to go bad, so I replaced it with an SSD,
| and figured I should upgrade the RAM while I had it open. I
| have Linux installed on it, and it's a nice media server box,
| running Jellyfin and a few other things. Only downside is
| that its support for HW video decode/encode is kinda limited
| -- no h265 -- due to its age.)
| MandieD wrote:
| Not sure if this is what you're thinking of, but One World
| Computing has found higher real RAM limits for various old
| Macs (this post is about the 2009 iMac I inherited): https:
| //eshop.macsales.com/blog/17059-late-2009-core-i5-i7-i...
| elzbardico wrote:
| Had one of those notebooks, and did the same thing. it was my
| second or third macbook, and I was used to buying the lesser
| spec'd machine and then beefing it up with more memory and a
| better HD or SSD
| pronoiac wrote:
| Same here! I'm bummed that Catalina, the last OS update to
| officially run on it, probably will hit EOL in 2022. I'll
| likely begrudgingly replace it, rather than look into
| workarounds to install newer versions, in an unsupported and
| slow way.
| neurostimulant wrote:
| You could install big sur using some patch if you don't mind
| the built in wifi card stopped working, but I heard you can
| swap the wifi card from later model and big sur would
| recognize it.
| benjaminpv wrote:
| I was looking to Hackintosh an older Dell desktop I had
| squirreled away and in the process of gathering all the hardware
| every piece of documentation I found _insisted_ that it topped
| out at 4GB. This was a late-era Core 2 so that seemed completely
| nonsensical to me (I don 't think I ever owned a Core 2 that had
| less than 8) and, wouldn't you know it, 8GB worked perfectly
| fine.
|
| Funnily enough, like the article's author I also encountered a
| DSDT-related problem on that same system: if you were to dump the
| tables and recompile them with the standard Intel utility it
| straight up wouldn't work. Came to find out that there are
| apparently two compilers, one from Intel and another from MS and
| the MS one is super-lenient about accepting garbage. Eventually
| worked out that the logic in the stock tables was such that
| several features (HPET and sleep, iirc) just straight up don't
| work unless the OS identifies itself to ACPI as Vista (and not
| like Vista+, Vista exclusively). Such a pain.
| secondcoming wrote:
| I remember having to faff about with DSDT code in order to get
| the battery indicator to work when running OSX on VMware Player
| (which you had to patch)
| toast0 wrote:
| I had some Dell Core 2 laptops that AFAIK were limited to 4G
| (well, less because it couldn't map anything above 4G so you
| wouldn't be able to access all the physical memory) by the
| Intel 945 chipset. If you had a 965 chipset you could do 8G
| apparently.
| hinkley wrote:
| There used to be people who would sell you memory for MacBooks
| or Fujistu laptops that nearly doubled the official RAM. My
| impression was that they didn't support arbitrary N GB cards
| but they did support a subset, and these guys just found a
| module that they did support.
|
| For my Fujitsu there was memory soldiered on the board so you
| couldn't quite double it, but you could get around half again
| as much memory as the manufacturer claimed was the max.
| comprev wrote:
| Although Apple said 8GB was the maximum a 2.4GHz Core2Duo
| Macbook Pro 13" mid-2010 could handle, the Intel chip inside
| could support 16GB.
|
| https://eshop.macsales.com/memory/maxram
| camhenlin wrote:
| This is true for many older Apple products. I have a
| similarly aged Mac Mini that officially only supports 8GB
| but took 16GB without problems
| illwrks wrote:
| I have one of these machines. That 16GB RAM bump and an SSD
| has resulted in it still being usable, 12 years after I
| bought it.
| applecore wrote:
| Wow. How has the battery in your MacBook Pro not died
| after 12 years?
| comprev wrote:
| Ditto! Resource heavy web apps used to make the laptop
| creak a bit but for 95% of tasks it was a solid machine.
| matheusmoreira wrote:
| I ran into DSDT problems as well on my laptop running Linux.
| How did you figure it out? How do people reverse engineer this
| stuff? I managed to get all USB features working but this ACPI
| stuff eludes me.
| npteljes wrote:
| Very nice adventure, and I love the fact that the open source
| ecosystem provided all the tools that OP could use to get ahead.
| MayeulC wrote:
| Does someone know what's happening with these PCI mappings?
|
| Is this memory-mapped by an address decoder on the motherboard
| (or north/south bridge)? Or is it a hint to the OS that they
| should map it here?
|
| Maybe the PCI I/Os are really there, hardwired on the
| motherboard, but use a higher impedance, though that would be
| very hacky.
|
| Or maybe they're mapped from that address, and the highest bits
| do not count, as address decoding is only performed on the lower
| bits? With physical memory shadowing parts of the physical
| address space?
|
| Or maybe this is just virtual address space shenanigans? In that
| case, how does the OS figure how to talk to PCI or the RAM based
| on the provided mappings?
|
| I might be able to find that information by looking at the
| specifications and whatever ACPI docs I can find, but if someone
| already knows how it works, I'd really appreciate a few pointers.
| stuff4ben wrote:
| I love posts like this! I remember back in the day having to cut
| motherboard traces on my Amiga 500 to get Fat Agnus to recognize
| 1MB of chip RAM. A pure BIOS/bootloader hack is far less risky!
| ComputerGuru wrote:
| This was shared on HN [0] when it was first written in 2019 and
| it was heavily discussed (817 points, 178 comments). As soon as I
| saw the title I knew what post this was; I recall it very vividly
| and was more than happy to upvote it and then sit down to read it
| again!
|
| [0]: https://news.ycombinator.com/item?id=19573458
| belval wrote:
| Most of the time those limits are important for a specific
| feature of the motherboard that you might not be using.
|
| For example I recently put 64GB of RAM in a mobo that only
| supported 32. It didn't work at first and through trial and error
| I found out that XMP was the only thing with a hard 32GB
| requirement. Once disabled it booted fine with 64GB.
| webdoodle wrote:
| Somewhat related, I had an older Asus core 2 board, that would
| accept 16gb of ram, but would only work on 64 bit OS's. However,
| even with a 64 bit OS, the onboard NIC would fail to work. So I
| added a NIC to the PCI bus, and it also wouldn't work. I could
| only get a USB dongle NIC to work. Really weird, and never solved
| why it was doing this.
| nayuki wrote:
| I had an easier experience along these lines. The Lenovo ThinkPad
| X220's official technical specifications say it only supports 8
| GiB of RAM. But many forum posts across the web confirm that
| people used 2 slots of 8 GiB = 16 GiB with no problem (e.g.
| https://www.reddit.com/r/thinkpad/comments/6rdra2/does_the_x...
| ). Sure enough, I tried it and it worked.
| walterbell wrote:
| Presentations on open-source firmware, which can be used to
| extend the lifespan of older motherboards and devices.
|
| 2020-2021: https://vimeo.com/user128699411
|
| 2019:
| https://www.youtube.com/channel/UCUVk2lv2h2VbP3Dx4k2axyA/vid...
| IntelMiner wrote:
| It's a shame that getting modern machines with Coreboot
| compatibility are virtually impossible
|
| I'd absolutely pay extra for a Ryzen 5000 series motherboard
| that I could put Coreboot on
|
| Hopefully the Framework laptop pushes things in the right
| direction for mobile computing, they've at least stated an
| intent to add Coreboot support
| znpy wrote:
| This post is so interesting, and someody already has archived
| that page: https://archive.md/p9uxC
| userbinator wrote:
| My experience has always been that "not supported" means anywhere
| from "physically impossible" (e.g. because there just isn't that
| many address bits) to "we won't help you because we haven't
| tested it".
|
| Some quick searching shows that others have managed to get that
| CPU to use 32GB of RAM:
|
| https://forums.overclockers.com.au/threads/p55-chipset-i5-75...
|
| I thought he would go as far as patching the BIOS itself, which
| would make it a "permanent" fix. In fact one of the projects I
| haven't gotten around to finishing is to patch the memory init
| code for an old Atom processor embedded motherboard to make it
| recognise more combinations of RAM modules; analysis of the BIOS
| and leaked sources shows that it was stupidly written as
| "if(512MB in slot 1 and 512MB in slot 2) ... else if(1GB in slot
| 1 and empty slot 2) else if(1GB in slot 1 and 1GB in slot 2)
| ...", when the memory controller can actually be set up generally
| to work with many more different configurations.
| jacquesm wrote:
| One end of that range should include 'you already have it but
| we're not telling you'.
|
| I noticed the type numbers of one of my computers had RAM that
| was 2x the quantity advertised and indeed with some fiddling I
| managed to unlock the second half.
| dmurray wrote:
| That's bizarre. RAM is relatively expensive and has long been
| a substantial cost of the computer. Not like CPU binning
| where it really can be cheaper to sell you the faster
| processor and lock it to behave like the cheaper one.
| jacquesm wrote:
| Yep. And this was when RAM was a lot more expensive than it
| is today. I could not quite believe my luck until it
| worked.
| ido wrote:
| I vaguely remember some Sinclair computers doing stuff
| like that because they used cheap RAM chips that were
| ensured to be error-free on the entire memory-space (so
| basically binning) so they used the "good" half, but a
| lot of the time the "bad" half was also fine?
| notreallyserio wrote:
| I went to the local store to buy 4MB (4x1) for a computer I
| was building but they accidentally gave me 16MB (4x4) for the
| same price. Then they went out of business, turns out it was
| a money laundering scam; guess they didn't know or care
| exactly what items went out the door.
| rzzzt wrote:
| "16 GB is not supported because the system has two slots and 8
| GB sticks do not exist" ...yet.
| wkearney99 wrote:
| and marketing didn't want some penny-pinching customer to
| fixate on HOW MUCH? would the system cost if it actually had
| all that RAM.
| olliej wrote:
| Haha, many many years ago I had a 486 motherboard, and through
| lots of sailing I was able to save to afford _2_ 8mb simms. I
| plugged them in and it reporter... 12Mb
|
| :-D
| ddingus wrote:
| I had a 5Mb 386 system for a while. Often, a program requiring
| 8Mb of RAM would work, just poorly on more than 4.
| kaliszad wrote:
| Yeah, one would expect, motherboards could have some heuristics
| to either: - have the best speed possible - have the highest
| capacity possible with the RAM available and finally - tell what
| is the problem if there is one (e.g. having no module in slot,
| having incompatible modules on channel)
|
| This cannot be so hard to do. See my recent adventures:
| https://twitter.com/KaliszAd/status/1462940387916582915
| [deleted]
| piyh wrote:
| I really appreciate writeups like this because it gives me
| insight into lower level systems that I previously did not know
| existed.
| exikyut wrote:
| I'm also always looking for additional low-level understanding.
| What's tricky is figuring out how to pace it so it's not
| overwhelming.
|
| Like, my favorite thing is that circuit boards have wobbly
| traces on them around high-speed interfaces (RAM, PCI, etc) so
| all the bits in parallel signals arrive at the same time. The
| clock speeds are specced right up at the edges of the speed
| electrons can stably flow at.
|
| And this sort of thing is awesome, but like... quite a fair bit
| beyond the point I'm practically able to engage at.
|
| I guess I'm trying to figure out how to leap without missing
| anything lol :D which is impossible now I phrase it like
| that...
| molticrystal wrote:
| For windows with test signing on it seems you may be able to
| replace the tables with your own generated ones similar to the
| OP's original attempt, but without the need to use grub. I have
| no idea the utility of this, considering it requires test signing
| and compared to the grub approach, but maybe it will come in
| handy to somebody someday.
|
| > To do this, rename the AML binary to acpitabl.dat and move it
| to %windir%\system32. At boot time, Windows replaces tables
| present in the ACPI firmware with those in acpitabl.dat. [0]
|
| [0] https://docs.microsoft.com/en-us/windows-
| hardware/drivers/br...
| csdvrx wrote:
| When you enable test signing (etc.) don't you then have the
| text overlay on top of the desktop wallpaper?
| ChrisArchitect wrote:
| Why did you share this?
|
| Some previous discussion:
|
| https://news.ycombinator.com/item?id=19573458
| ChrisArchitect wrote:
| (2019)
| Nux wrote:
| I'm glad he did as I missed it before. Perfectly happy for
| items of interest to be reposted periodically, it makes sense.
| ChrisArchitect wrote:
| Just asking _why_. Why submit it. There 's nothing new on it.
| We're just repeating the same discussions had before that can
| be read on the previous discussion when it was new. Hence
| linking to the other discussion thread.
| oauea wrote:
| > In order for the document to help me, I clearly needed to find
| the four error parameters that used to be displayed with the blue
| screen on older versions of Windows. Windows 10 hides all the
| information by default, but I discovered that it's possible to
| re-enable display of the extra error information by adding an
| entry to your registry.
|
| It's still baffling how microsoft completely broke bluescreens by
| hiding any useful info.
| mdaniel wrote:
| Fascinating; so that makes me wonder if the bluescreen code
| flow _also_ tries to look up the registry value, or if the boot
| process somehow reads that registry value so early in the boot
| that by the time a bluescreen happens, the value is already
| available to it ... in a specific memory location or something?
|
| It's my idea of hell having an error handler that tries to do
| fancy stuff and then the error handler dies and swallows the
| original error condition
|
| Also, if you happen to still have the link to that regkey
| description, I bet this audience would benefit from your
| research
| grishka wrote:
| It's part of the deplorable ongoing effort by the IT industry
| as a whole to dumb everything down as much as possible.
| kube-system wrote:
| Blue screens got a bad reputation because the people they
| were most often presented to had no idea how to consume the
| information. Presenting the right information to the right
| people is also important.
| asddubs wrote:
| but the screenshot after enabling it just has 4 numbers in
| the top left corner in blue-on-blue text. i think most
| people would ignore those, since there's also a large plain
| english error message.
| kelnos wrote:
| But even if most people don't know how to consume it, it's
| a lot easier for a tech support rep to just ask for the
| numbers, rather than see if booting into safe mode or
| whatever will work well enough for them to walk the
| customer through manually adding registry entries (which
| just seems like a bad idea anyway), so they can get the
| extra debugging info.
|
| Just leave it visible all the time, Microsoft! It won't
| hurt, and can certainly help!
| kube-system wrote:
| I have religiously put debugging information into my
| error messages for the past decade. Often accompanied
| with a statement like "Please provide this information
| when reporting this error". I have supported thousands of
| users. I can count on one hand the number of times that a
| user has provided that debugging information to me when
| it was appropriate to do so. I am the only one who uses
| that debugging information, when I'm running my own
| tests.
|
| In fact, sometimes I'll get support requests like "Hey I
| got this error 012345 what does that mean?" and the
| attached screenshot will show a message like: "Invalid
| Password, please type your password again (Error code:
| 012345)"
|
| I absolutely understand the technical utility, but I
| really wouldn't be surprised if they have better overall
| support outcomes without it.
| hulitu wrote:
| > Just leave it visible all the time, Microsoft! It won't
| hurt, and can certainly help!
|
| It is not MS style. Not so long ago they were blaming
| sysadmins for 404 errors.
| grishka wrote:
| Everyone knows that a blue screen means that the OS
| crashed. Maybe they should be more helpful instead? Like,
| you know, actually show a human-readable description of the
| error, so the person who sees it knows where to start
| troubleshooting. Something like "kernel-mode driver for
| device X performed an invalid memory operation, please try
| updating it or report this to its developer" instead of
| "PAGE_FAULT_IN_NONPAGED_AREA".
| kube-system wrote:
| I generally agree, but I don't think
|
| > "kernel-mode driver for device X performed an invalid
| memory operation, please try updating it or report this
| to its developer"
|
| is a good example of a user-friendly error message
| either.
|
| My experience in writing software and supporting it for
| end users (even highly educated users) has taught me that
| a large percentage of people will stop reading if they
| encounter any technical words or indirect statements.
| Honestly, I feel like the "Your computer ran into a
| problem and needs to restart. We'll restart it for you"
| message that Microsoft settled on is probably about the
| common denominator. It has no technical terms and it
| doesn't give the user an opportunity for decision
| paralysis.
| elzbardico wrote:
| People got more impatient over the years and now expect
| things just to work. I had a computer shop in the late
| 90s (my first and only business ever) and as lot of my
| clients where pretty much helpful with their observations
| when they brought their machines for me to fix.
|
| It is not that people were smarter, of course, but they
| did expect to have to dirty their hands with their stuff
| from time to time. Nowadays, besides all of our protests
| at the contrary, stuff is way more reliable and ease to
| use, and people got used to complicated stuff just
| working.
| grishka wrote:
| > People got more impatient over the years and now expect
| things just to work.
|
| Except most of the time, things aren't aware of that.
|
| Yes, today's operating systems are more reliable thanks
| to memory protection and better abstractions. But that's
| compensated by insatiable product managers that
| absolutely have to keep updating a feature-complete
| product at any cost with features and UI redesigns no one
| ever asked for.
| kube-system wrote:
| Agree 100%. The idea of "what a computer is" and "who a
| computer is for" has changed quite a bit. I sometimes
| forget how far computing has come until I see an old news
| segment:
|
| https://www.youtube.com/watch?v=0KDdU0DCbJA
| userbinator wrote:
| Not sure if it's "IT industry as a whole", or Microsoft,
| because if I'm trying to do tech support for someone, I
| definitely want that extra information.
| barrkel wrote:
| The missing contents are also in the system eventlog entry, but
| that presumes that you can reboot to see it.
| marcodiego wrote:
| Previous discussion:
| https://news.ycombinator.com/item?id=19573458
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