Author Topic: How much RAM do you have on your PC? (Read 87,626 times)

Lashiec · « **Reply #25 on:** September 18, 2007, 08:10 PM »

Hey, I was working with a computer with an astounding 80K of RAM during the 90s...

mwb1100 · « **Reply #26 on:** September 18, 2007, 08:22 PM »

PAE won't necessarily get you back the missing bit of your 4GB - it depends on whether or not the motherboard makes the RAM that would 'overlay' the address space reserved for devicea available in a different area of the physical address space. My guess is that virtually none do, so you lose that 512-768MB regardless of PAE or a 64-bit OS. If anyone knows for certain of a desktop motherboard that supports mapping the missing RAM above the 4GB address space, please post details.

For gory details on this:

Quote from: "http://www.codinghorror.com/blog/archives/000811.html"

The proper solution to this whole conundrum is to use a 64-bit operating system. However, even with a 64-bit OS, you'll still be at the mercy of your motherboard's chipset and BIOS; make sure your motherboard supports using 4 GB or more of memory...

Quote from: "http://www.interact-sw.co.uk/iangblog/2005/08/05/is3gbenough"

If you're lucky, your PC will be able to do something clever. The usual solution is to make that last gigabyte appear further up in the memory map. So your memory map looks like this...

...

How can you know which kind of motherboard to buy in order to avoid this? Right now it's not all that easy to tell actually, short of reading the datasheets for the chipset... If the mobo can take more than 4GB of memory, then you might be OK. Although they might just take the attitude of "If you can afford to fit 32GB of memory, you can afford for 1GB to go missing"...

Also, note that none of this has anything to do with the /3GB switch or the amount of memory available to applications, since they deal with virtual memory not physical memory (unless the application is specifically written to take advantage of the PAE APIs in windows, which pretty much none do except for the industrial-strength databases).

f0dder · « **Reply #27 on:** September 18, 2007, 11:24 PM »

I haven't relaly seen any disadvantages from turning on PAE; you can turn on PAE but still have DEP only set for the "critical system services". I've been running with DEP for everything for a while now, haven't seen any incompatibilities yet, and haven't felt a speed hit either (but I haven't done any benchmarking of it, and I do have NX-capable hardware so it's not emulated).

masu · « **Reply #28 on:** September 19, 2007, 07:09 PM »

I have now updated my PC with 2GB RAM, and the speed increase is really noticable, even under Windows Desktop
Thanks for your advice

Cynic · « **Reply #29 on:** September 25, 2007, 09:06 PM »

Quote from: cranioscopical on September 17, 2007, 07:35 PM

Quote from: katykaty on September 17, 2007, 07:19 PM
4 GB - though I'm on XP so only get 3.25. But at the prices these days why have less?

My thought exactly, though it was a little frustrating at the time of purchase

A bit OT:
I also have 4GB of RAM installed, and 32 bit XP only sees 2.93 GB. No surprises here, I suppose.

What's puzzling me is that when I go to the BIOS, the motherboard only sees 3008 MB as well. Shouldn't it see all 4 GB? Even if one the four 1 GB modules wasn't working correctly, I should have at least 3072 MB, right? Why only 3008?

f0dder · « **Reply #30 on:** September 25, 2007, 09:12 PM »

Cynic, look through the BIOS settings to see if there's some RAM remap options. Also, PCI (and PCI-e and AGP) devices can require memory mapped I/O, which will eat part of the *address space* (even though not the physical RAM) - you need PAE mode, and XP might be braindead about that.

Cynic · « **Reply #31 on:** September 25, 2007, 10:10 PM »

I remapped and now the motherboard sees all 4 GB, but XP only sees 2, instead of 2.93. Should I disable memory remap again?
In the General tab of the System Properties window opened when right-clicking the My Computer icon says "Physical Address Extension". Does this mean PAE mode is already enabled? Why then only 2 GB?

f0dder · « **Reply #32 on:** September 26, 2007, 09:32 AM »

Hm, perhaps it's artificial limitations built into XP - this MS arcticle says XP supports "AWE API and 4 GB of physical address space", instead of 4GB of RAM - bastards.

The BIOS "remap RAM" options, as far as I understand it, remaps your physical RAM to higher-than-4GB in the address space, meaning you can access it in 32bit-PAE or clean 64bit mode, without conflicting with memory mapped hardware. But if MS artificially restricts you to 32 bits of address space, I guess there's nothing to do, except going 64bit or getting a server edition of windows.

Carol Haynes · « **Reply #33 on:** September 26, 2007, 09:55 AM »

Doesn't answer the question why WinXP went from recognising 3Gb to 2Gb ?

Just reading my motherboard manual (ASUS A8N32-SLI Deluxe) and it says the following:

Quote

If you install four 1Gb memory modules, the system may detect less than 3Gb of total memory because of address space allocationfor other critical functions. This limitation applies to Windows XP 32-bit version operating system since it does not support PAE mode
If you use Windows XP 32-bit version operating system we recommend that you install less than 3Gb of total memory.

Seems to fly in the face of what MS says - but I guess what they are saying is that critical fundtions (such as other mapped memory from graphics cards etc) are removed from the 4Gb space.

Here is another article - this time for VISTA which is a bit clearer and supports that interpretation:

http://support.microsoft.com/kb/929605/en-us

f0dder · « **Reply #34 on:** September 26, 2007, 10:59 AM »

Carol, using the "memory remapping" thing maps the additional memory above the 4GB (and thus 32bit) marker. XP probably isn't just limited to "4GB of address space", but "the first 4GB of address space". Lame with artificial limitations, and they could at least have made it physical memory instead of address space. And XP does support PAE, it just imposes artificial limitations...

Carol Haynes · « **Reply #35 on:** September 26, 2007, 11:10 AM »

I agree MS says XP 32-bit supports PAE - but it obviously has problems doing so (according to ASUS). That was a direct quote from the ASUS manual.

The second article I quoted says that even with Vista you are limited to 4Gb (less Direct Memory IO device space requirements) and that Vista 32-bit imposes a default limit of 3.12Gb on available memory.

The article specifically says that the workaround to get the full 4Gb is to use a BIOS that supports memory remapping AND a 64-bit OS AND specific CPU types

f0dder · « **Reply #36 on:** September 26, 2007, 11:19 AM »

Carol: XP doesn't have problems supporting PAE, it simply imposes artificial limitations on how much it supports, for market segmenting reasons. Would be interesting testing a pre-SP2 XP and see if it supports more RAM, because according to the MS link pre-SP2 had the limit physical memory, not address space.

But yes, ASUS is right that you need chipset+bios combo that supports memory remapping, because of memory mapped devices.

cranioscopical · « **Reply #37 on:** September 26, 2007, 01:44 PM »

Quote

But yes, ASUS is right that you need chipset+bios combo that supports memory remapping, because of memory mapped devices.

I chose my mobo for reasons other than RAM capacity but when I saw that it accommodated 4 Gigs that's what went into it.

I should have RTFM, I suppose. Utilities can see the 4x1024MB sticks but XP only 'allows' 3199MB. As you all have noted, PAE doesn't help with this.

Given the high prices that we used to pay for RAM as recently as 10 years ago, I can't say that this really matters very much. I've always found that adding as much RAM as possible is a good first step on the road to avoiding computer woes.

Cynic · « **Reply #38 on:** September 26, 2007, 04:26 PM »

Quote from: cranioscopical on September 26, 2007, 01:44 PM

I should have RTFM

So should I: my motherboard is an ASUS P5B Deluxe, and not only the manual advises not to install more than 3 GB with XP 32 bit, it also states that I should have bought memory with the same CL. My old 2 GB are CL=5, whereas the newly acquired are CL=4.
I knew beforehand that XP wouldn't recognise all 4 GB, and I also knew that the faster memory would have too run at the same timings as the slower, but two 512 MB modules with CL=5 were only 25€ cheaper than the two 1 GB CL=4 modules I opted for, so I thought it would pay off to purchase the extra GB, since I'll probably move to 64 bit someday... I just hope I won't get into any stability problems because of this decision.

Lashiec · « **Reply #39 on:** September 26, 2007, 05:15 PM »

Hmmm, as long as you don't put them in dual channel, you won't have problems. Dual channel is very sensitive to different latencies with the RAM sticks, but there should be no issues if you don't use it. Of course, you will lose a bit of performance, but not much.

The question is if you can use dual channel using each pair of sticks with the same latency...

Cynic · « **Reply #40 on:** September 26, 2007, 06:31 PM »

I believe I have them in dual channe, in CPU-Z's Memory tab, Channels # indicates "Dual", and the reported latencies are equal to the slowest pair (5-5-5-18, whereas the new pair is rated 4-5-5-12).
I had the first pair in dual channel (on same coloured slots) prior to the purchase, so I added the new pair in the empty slots.

Lashiec · « **Reply #41 on:** September 26, 2007, 06:36 PM »

Well, then it's supported. If problems arise, though, you know what may be the culprit

. For your peace of mind, MemTest86+ running a whole night could be a good idea.

lanux128 · « **Reply #42 on:** September 27, 2007, 02:06 AM »

a non-related question: can i mix PC2700 DDR RAM with PC3200 DDR? both are 256MB..

Lashiec · « **Reply #43 on:** September 27, 2007, 02:29 AM »

Yep, the only issue is that the the PC3200 stick will run at a lower rate to match the one of PC2700, but apart from that no problem (unless things changed since I ran sticks of RAM with different speeds). Apply the dual channel caveats mentioned above (just for precaution) and you'll be safe.

lanux128 · « **Reply #44 on:** September 27, 2007, 02:34 AM »

ok, thanks! going to try out now.. if i don't come running to you again, consider everything went fine..

Cynic · « **Reply #45 on:** September 27, 2007, 07:17 AM »

Quote from: Lashiec on September 26, 2007, 06:36 PM

For your peace of mind, MemTest86+ running a whole night could be a good idea.

Thanks.
I did what you suggested, and it reported no errors after 14 passes lasting more than 8 and a half hours. I had memory remap disabled, so I think it only tested 3008 MB, I'll enable it now and let it test the full 4 GB for another few hours.

Nighted · « **Reply #46 on:** September 27, 2007, 07:34 AM »

I don't keep RAM on my PC. I prefer to keep it inside attached to the motherboard.

Darwin · « **Reply #47 on:** October 16, 2007, 04:26 PM »

Yippee! I bought two cheap DDR333 sticks - 1 GB each - and installed them into my notebook's motherboard (I WAS paying attention, Nighted!) and it's been recognised (Darwin jumps up and down for joy and generally makes an ass out of himself... Business as usual). As I noted in this post earlier in this thread, my notebook was *supposed* to be maxed out at a gig. I'm so happy I could... Ah, there simply aren't (polite) words. It feels like a brand new notebook!

PS was emboldened to try this because my wife's notebook takes DDR333 RAM and I would have lost nothing if it didn't work in mine (which supports RAM up to 266MHz...).

scancode · « **Reply #48 on:** October 16, 2007, 04:32 PM »

** happy upgrade; now running in 768MB :-] **

nosh · « **Reply #49 on:** October 16, 2007, 05:26 PM »

I'm running 1GB on a P4-300MHz. The RAM never seems to get maxed out, it's always the CPU that seems to be the bottleneck. Would it make sense for me to go for 1 GB more considering I'm not even using my current capacity to its full potential? Will XP or any apps behave differently if they detect considerably more RAM?

On a somewhat related note the only sluggish apps are Winamp (hardly used since I discovered Foobar2000) and Firefox (42 extensions

, but none of them unused.) FF consumes something like 80-140 MB RAM on average, is there some way I can actually get it to use more and speed up?

Edit: This article is an interesting read. It recommends 2GB for "heavy users" but their benchmark graphs show a marginal difference in performance between 1 and 2 GB. Some unexpected results too - like, it's faster decompressing a large RAR file with 512 MB RAM than with 2GB.