how to find what device is decreasing available RAM

See this

 

 

http://www.asisupport.com/ts_4GB_memory_info.htm

 

 

 

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Thanks for the link, mombodog. The article and the ones referenced in its links contained an excellent summary of the issue I am facing, where hardware components on the motherboard are reserving enough physical RAM that the amount available to the OS (and, therefore, our app) is reduced. Although I knew the details contained in these articles, they were an excellent resource as I explained the issue to management.

But my original question wasn't, why is this happening? It had to do with determining which components were eating that memory, and is still unanswered. I mentioned that the HP workstation we used prior to the Dell T5500 did not cause this issue for us; after it booted, the amount of RAM available was reported as 3.6 GB. I did not mention that we were using a Dell T5400 briefly, until Dell discontinued that product and we were forced to switch; after the T5400 booted, the amount of RAM reported was 3.5 GB. So, something changed when we went from the T5400 to the T5500 that costs us 750 MB of RAM, and that something that changed was not the OS.

The advice offered in the articles is to upgrade to a 64-bit OS. That is our plan, but in the short-term, the option is not possible for us. We are reliant on a hardware vendor who does not have a native 64-bit driver, and whose 32-bit driver does not work when windowed in Vista 64 or Win7 64. Although this vendor is working on a solution, it is many months away. The cost to us for switching away from this vendor is also in terms of many months. So, in the short-term, switching to 64 bits is not an option.

Our choices are presently limited to 1) finding a way to configure the T5500 so that this RAM overhead is reduced to an acceptable level, or 2) finding an alternate system that provides equivalent functionality without the RAM overhead. The article does suggest that OEMs may be able to configure their BIOS to reduce the RAM overhead. It is this option that I am trying to investigate. For reasons I cited in my first email, I suspect that the components mentioned in other email threads on this forum (video card, RAID controller) are not at fault here. I do not know how to discover for myself where the memory requirements are proceeding from. Once I discover that, I can look into whether these are configurable in a way that preserves our critical functionality while reducing the RAM overhead.

Any ideas?

Thanks, PC

I don't know for sure, but I think it has to do with how much hardware is present on the motherboard as to how much of the installed memory is reserved for that hardware. Looks like they are pushing us toward 64bit. You might poke around in the bios, see if there is any hardware you can disable that you don't need, see if that frees up some memory in Windows.

http://support.dell.com/support/topics/global.aspx/support/dsn/en/document?c=us&cs=19&dl=false&l=en&s=dhs&docid=BF4C8393BFC74A83B9EC318630B9CE7D&doclang=en

"On Dell's newer lines of desktops, PCI-Express uses 500 megabytes (MB) in the map; integrated video takes 256 MB right below PCI-Express, leaving 3.25 GB of memory available to the operating system via RAM. In some cases, less RAM is available depending on what other add-in cards are installed. "

 

You might try enabling PAE. Does not sound like a solution but may be worth a try.

http://www.tipandtrick.net/2008/how-to-enable-pae-in-x86-32-bit-windows-server-2003-and-2000-to-use-large-4gb-or-more-ram-memory/

Please post back if you do find a solution.

 

Did you look in system Information to see where the memory is allocated?  Hardware Resources>Memory

It wont show you how much memory is used, but will show you what hardware is reserving it, maybe compare to another system that is using less.

 

 

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Philip Coveney,

Thank you for contacting the Dell Community Forums.  What video card is installed in your T5500?  We have seen an issue where certain video cards cause a decrease in the amount of available RAM comparable to what you described. 

Chris, thanks for your interest. It’s an NVIDIA Quadro FX 580.           

 PC

Philip Coveney,

Thanks for the information.  What version of the BIOS are you running on your T5500?  We did see an issue where the Quadro FX 580 caused a decrease in available RAM like the one you described, and the most current version of the BIOS (A03, available here) has been shown to improve performance.  If you are not currently at A03, please try flashing to that BIOS and see if that helps.

We are running A03. Is there a technical note somewhere, describing the issue with the Quadro board? It would be interesting to see what the before-and-after statistics were when the BIOS was upgraded, even if that is not a solution for us.

Philip Coveney,

I searched our support knowledge base, but it looks like we don't have a techncial note about the issue available currently.  Since the A03 BIOS didn't resolve the issue for you, can you try installing the latest drivers from NVIDIA's site and see if they have any effect?

Philip,

I think your analysis is correct.  There are two possible resolutions for this issue:  1. Reconfigure the system BIOS so that the graphics card doesn't have such a pronounced effect on available memory in the OS.  2.  Obtain a different system or a different video solution.  (Installing a 64-bit OS might help also, but I'm seeing reports of people having this problem while running x64 versions of Windows.)  Dell engineering attempted to address the issue with the A03 BIOS release, which featured an updated algorithm to change the amount of memory available to the OS.  That did actually help some customers, but unfortunately it did not resolve the problem on your system. 

As for trying a replacement system: This situation has been seen on different systems using different cards (see this forum thread for an example), so it's not clear that purchasing a different computer will produce different results.  I'm researching the issue further, and will post here if I find a better solution.

We installed the latest NVIDIA drivers quite early in the troubleshooting process. I just checked, and NVIDIA has made no driver updates since we did this. But, aren't we getting ahead of ourselves? I would guess that there is someone at Dell who evaluated the motherboard design for the T5500 (or, perhaps, created the motherboard design for the T5500), and is aware of which components have what impact on the RAM memory footprint. I mentioned earlier that we have 2 options with respect to this problem: 1) re-configure the T5500 BIOS so the memory footprint is reduced, or 2) find a system equivalent in performance that does not have this issue. Because we have spent some time looking at the BIOS configuration options, I am not optimistic that this will end up being our solution (but--would be happy to be wrong!) With respect to the second option, I will have the same requirements of any proposed replacement system: we would need to know what the memory footprint is, what components are contributing to the RAM overhead. So, even if we don't go with the T5500, it seems I need to be able to talk with someone at Dell who can knowledgeably discuss the component requirements for various systems. Does this seem reasonable? PC

>>Dell engineering attempted to address the issue with the A03 BIOS release Could I see what documentation you are seeing describing a reported problem and the BIOS change? >>Obtain a ... different video solution How do we know it's related to the video card? That's what I meant by, aren't we getting ahead of ourselves? Why don't we believe, for example, it's the RAID controller (cited in other threads)? >>Installing a 64-bit OS might help also As I mentioned to mombodog: "The advice offered in the articles is to upgrade to a 64-bit OS. That is our plan, but in the short-term, the option is not possible for us. We are reliant on a hardware vendor who does not have a native 64-bit driver, and whose 32-bit driver does not work when windowed in Vista 64 or Win7 64. Although this vendor is working on a solution, it is many months away. The cost to us for switching away from this vendor is also in terms of many months. So, in the short-term, switching to 64 bits is not an option." So, in other words: this is good advice, that I am presently unable to follow. >>so it's not clear that purchasing a different computer will produce different results As I mentioned to mombodog: "I mentioned that the HP workstation we used prior to the Dell T5500 did not cause this issue for us; after it booted, the amount of RAM available was reported as 3.6 GB. I did not mention that we were using a Dell T5400 briefly, until Dell discontinued that product and we were forced to switch; after the T5400 booted, the amount of RAM reported was 3.5 GB. So, something changed when we went from the T5400 to the T5500 that costs us 750 MB of RAM, and that something that changed was not the OS." So, we have recent experience with systems from 2 different vendors that it is possible to build a WinXP system with our performance requirements that boots with at least 3.5GB of RAM available to the OS. I would claim that is convincing evidence that purchasing a different computer will produce different results. The problem is, I need to have a way to evaluate whether a given motherboard/hardware component configuration does or does not leave the OS with enough memory for our app to function properly. I believe you when you say there is no documentation in your knowledge base concerning the memory requirements of certain components when installed on certain motherboards. However, it seems inconceivable to me that Dell's engineering groups would not have performed this evaluation themselves, as they designed the (motherboard that goes into the) product. Are such documents available to you? Thank you for your continued efforts.

Philip,

The reason I suspect the video card in this case is that the system BIOS and OS typically allocate memory addresses to core hardware components before allocating addresses to RAM, and the BIOS specifically allocates additional system memory to expansion video cards when present (see this thread and this thread for examples of what I'm talking about).   So it seems likely that the additional memory being set aside for the video card is responsible for the decrease in available RAM that you're seeing, especially considering that the T5400 had a very similar integrated RAID controller, but did not have this problem.  This can't be completely fixed, due to the limitiations of 32-bit operating systems, but sometimes can be partly alleviated by changing the routine the BIOS uses to assign memory to the card.  That's what the A03 BIOS was designed to do, but for some reason it did not resolve the problem on your system.

As you are aware, the long-term resolution to this issue is to migrate to a 64-bit OS, but since that's not an option in your case (which is understandable--many customers are in the same condition), we have to look at other alternatives.  Unfortunately, I don't have access to the specifications that Dell engineers use when computing motherboard resource requirements.  Do you still have any T5400s available, and if so would it be possible to install the video card from one of those systems in one of your T5500s as a temporary test?  I believe you may be able to resolve the issue in the short term by changing video cards, but swapping with one from a T5400 would confirm that.

 

Chris,

No, we don't have anymore T5400's, but I did take another NVIDIA card from another system and swap it in. (In retrospect, a test I should have performed long before...sorry.) The reported RAM went up from 2.75 to 3.25. So, the graphics card is eating half a gig, which is equal to the amount of onboard RAM it contains. I have visited NVIDIA's tech support about configuring the graphics card, but they have referred me to the board's manufacturer; in other words, they supply the chip(s), but don't actually make the Quadro FX 580?  Who does? Dell?

I am going to investigate using a different graphics card, but I would like to continue tracking down what is eating the other three-quarters of a gig. Any thoughts?

PC

Philip,

I think Dell does make the board, but am not 100% sure.  I checked our internal documentation for that card, but it didn't say one way or the other.  For what it's worth, this arrangement (where NVIDIA provides the GPU but another company supplies the board) is used by other card manufacturers also (like PNY--see here for an example). 

To answer your second question, the remaining 3/4 of a gig is used by other system devices, including the BIOS, motherboard components (integrated controllers), expansion slots, etc.  In a 32-bit envrionment, those devices actually have priority when memory addresses are allocated, and RAM gets what's left.  Most 32-bit OSes will show between 3.25 and 3.5 GB available ( Vista SP1 will show 4 GB available, but that's cosmetic--1/2-3/4 of a gig is still allocated to I/O, so the OS can't really use it all).