Can /3GB switch be used when the PC has a 1GB video card?

[Psyringe]

Is there someone here who uses the /3GB switch on a system which has a 1 GB graphics card? If yes, please shout, as I'm currently wondering whether that's possible.

I'm playing highly modded Civ4 on Windows XP SP3. Due to the added content and larger maps, Civ4 needs more than the 2 GB address space that XP allows applications, so I'm using the /3GB switch. However, I ran into graphics problems when I first tried that (some years ago), so apparently the remaining 1 GB of address space wasn't enough for Windows and all other kernel stuff to work. I then fine-tuned the split with the /USERVA setting until the graphical glitches were gone.

I'll upgrade my video card shortly. The old one is an nVidia 7600 GT with 256 MB of RAM. The new one will probably be an ATI Radeon HD 5570 with either 512 or 1024 MB of RAM.

My concern is: Since the new video card has more RAM, will it use up more address space as well? If yes, will I have to allocate even more address space to the kernel than I currently do? If so, would it be better to buy a 512 MB card (since it would leave more address space usable for the game) than an 1GB card?

Some help from people with practical experience with the matter would be greatly appreciated. So far, I've phoned up a number of hardware vendors, who either confused address space and physical or virtual RAM, or assumed that I wanted to add my VRAM to the physical RAM usable by the OS, or apologized and said that this question was too technical for them (at least those were honest). Apparently everyone without experience in using the 3GB switch (and knowledge about what it actually does) is bound to misunderstand the question, or perhaps I'm just horribly bad in making myself clear, I wouldn't rule that out. In any case, if you're using the /3GB (and perhaps also /USERVA) switch on a Windows XP system with a graphics card that has a lot of memory, please tell how it worked, thanks!

 

[tokala]

I'll upgrade my video card shortly. The old one is an nVidia 7600 GT with 256 MB of RAM. The new one will probably be an ATI Radeon HD 5570 with either 512 or 1024 MB of RAM.

I was using a 8800GT 1024 MB with WinXP 32 bit /3GB enabled for a while. Had 3.5 GB (or even 3.75 GB, can only remember that I lost way less than expected )

Worked without any abnormal behaviour in Civ4/FFH and its modmods

I think it's mostly depending on the mainboard how much memory you lose.

Unless you have a 2560x1600 screen and/or use those bloated texture modpacks for Oblivion or the likes, the 512MB version of the 5570 will be exactly as fast as the 1024 MB version, if having otherwise identical memory specs. Just make sure to get a GDDR5 or at least DDR3 version

Edit: board is an ASUS P5N-E SLI with nforce 650i chipset, in case you are interested.

 

[Psyringe]

Thanks, that's the info I was looking for.

If the amount of address space used up by a "large" video card is dependent on the mainboard (or perhaps the drivers, I guess these could be a factor as well), then I can't be sure how a 1 GB card will behave on my machine - however, your report makes clear that a 1 GB card doesn't necessarily use up a lot of address space, so it's worth a shot. I'll see if I can find a vendor who agrees to letting me return the card in case it's demanding for my purposes.

My mainboard is rather old btw (Asus A8N5X), I'll check whether there's any info about this board and how it handles cards with a lot of video ram.

I'll probably go for DDR3 memory - one of the advantages of the 5570 (for me) is the very low power consumption. I've seen reports about DDR5 versions' power consumption under load being nearly 50% higher, and I'm not sure yet whether the increased performance is worth that for me.

Again, thanks for your help. Also, if others have experience with these things as well, please post - especially if the issue is indeed mainboard dependent; in that case having data from different mainboard would help to round the picture.

 

[tokala]

I'll see if I can find a vendor who agrees to letting me return the card in case it's demanding for my purposes.

Fernabsatzgesetz

I'll probably go for DDR3 memory - one of the advantages of the 5570 (for me) is the very low power consumption. I've seen reports about DDR5 versions' power consumption under load being nearly 50% higher, and I'm not sure yet whether the increased performance is worth that for me.

I would like to see those reports
Memory power consumption should be almost irrelevant on a video card, compared to what the GPU itself is guzzling. And the 5570 in any incarnation is pretty thrifty. Even under furmark torture it stays below 40W. I can't imagine any case or PSU that cannot handle that

 

[Psyringe]

Fernabsatzgesetz

Yup.

I would like to see those reports
Memory power consumption should be almost irrelevant on a video card, compared to what the GPU itself is guzzling. And the 5570 in any incarnation is pretty thrifty. Even under furmark torture it stays below 40W. I can't imagine any case or PSU that cannot handle that

I got that figure from a test at tom's hardware (and a bit of interpretation, admittedly).

The first graph in this test shows (among others) two systems with 5570 cards, one with DDR3 and one with DDR5 memory. The formers system draws 187 Watts under load, the latter 206. Since the systems were otherwise identical, the 20 watts difference must be caused by the graphics cards, and the memory speed was the only difference between those that the testers found worthy of mention. Given that AMD's reference 5570 card comes with a max power consumption specification of 42.7 Watts, these 20 Watts amount to about 50% higher power draw by the DDR5 card.

I'd be glad if I were wrong (because then buying the faster card would be a no-brainer considering that I can get a 512MB/DDR5 card for the same price as a 1GB/DDR3 card and don't have much use for the additional memory of the latter), and I might well be (since I knew virtually nothing about post-2006 graphics cards before yesterday), but it seems to me that this reasoning is correct?

Regarding whether PSU can handle the load: It probably can in any case, but for some reason I keep burning PSUs, it's already embarrassing when I show up at my main vendor with another one (although they keep replacing them since they're usually still under warranty). Having the machine run 24/7 might be a factor here, but in any case I try to not put more load on the system than I need, hence I'm looking for a video card with good "performance per watt" specs. Additonally, my personal experience is that low-consumption cards are more durable than high-consumption ones. Point in case, I never fried a graphics card - the only fried graphics card I've ever seen in 20 years of tinkering is the nVidia 7950 GT that I just removed from my girl friend's machine (which is also the reason why I'm looking for a new one now, she'll get my 7600GT).

Btw, in case someone's interested, I found a resource that explains some intricacies of how the BIOS maps external memory into the main address space. the document was meant for Intel's internal training, which is probably the reason why it's actually useful. It only deals with Intel chipsets though, but since AMD users tend to face the same inconsistencies regarding how much memory is "lost", it's probably not much different for those: http://dlsvr.asus.com/pub/ASUS/mb/4GB_Rev1.pdf

 

[tokala]

I'm usually extremely sceptical about anything THG is coming up with, but in this case they might have a point
Most other reviews have measured only the DDR3 version, as very few 5570s come with GDDR5. And most "respectable" geek sites won't bother long with such lowly cards anyway. In reviews where the GDDR5 version was used, total system power consumption was closer to the 5670 than to the 5570 DDR3, so it looks like GDDR5 memory indeed leads to a significant increase in total system power consumption for low-powered cards. Some of the difference can be certainly attributed to the CPU running higher (being less GPU-limited), but as you are only interested in what the PSU has to provide, that won't matter

But in the great scheme of things, a 7600gt, 5570 or 5670 are very low powered video cards, any PSU upwards of 300W should be able to handle a s939 system with one of those
If you keep frying PSUs, I wouldn't rule out the possibility that your mainboard is destroying them.

Just skimmed that whitepaper, did I interprete it correctly that only device types and device numbers matter, not how much physical memory each device has? In that case you could just choose any card you like

 

[Psyringe]

But in the great scheme of things, a 7600gt, 5570 or 5670 are very low powered video cards, any PSU upwards of 300W should be able to handle a s939 system with one of those

It probably is; I just developed a preference for components with low power consumption over time. However, after reading up a bit more, I'll probably get a 5670 instead of a 5570 - needs a bit more power, but (as you said) it's still a low powered card, and the increased performance justifies it imho.

If you keep frying PSUs, I wouldn't rule out the possibility that your mainboard is destroying them.

Dunno, I had three different mainboards in the last 8 years, and the PSU problems were pretty consistent. It's not that I need a new one every month though, they just seem to give in sooner than they should. I think the most likely cause is that 40-Euro-PSUs probably aren't intended for continuous usage over weeks and months.

Just skimmed that whitepaper, did I interprete it correctly that only device types and device numbers matter, not how much physical memory each device has? In that case you could just choose any card you like

I think the required allocation space can be independent of the device's physical memory, but for graphics cards it usually isn't. Section 2.2 of the paper has two example memory maps. Note that especially the PCI Enumeration Area 2 (512 MB will only by allocated when the BOS thinks that the graphics card will need it.

 

[Lemon Merchant]

@Psy:

I've used the /3GB switch with a 1 GB card, and it worked just fine. Although my motherboard had a "remap" feature that would relocate some hardware memory addresses above the 4GB boundary. I've been using a 64 bit OS for a couple of years now, so I haven't thought about it much, but I still play Civ on my laptop once in a while, and it has a 32 bit OS. I really didn't notice any improvement in the game with the switch enabled, TBH.

As for PSU's, a good OCZ or Corsair supply should set you back about $100 USD, and they really stand up in my experience. I've blown a few CPU's, and had a graphics card catch fire, but my lil' ol' OCZ wasn't the cause, and it's still ticking along.

 

[Psyringe]

I really didn't notice any improvement in the game with the switch enabled, TBH.

The only improvement that the /3GB switch brings is that the game doesn't crash if it tries to allocate more than 2 GB of memory. Unmodded BTS never gets that far, but if one adds a lot of content and plays on super-huge maps with lots of civilizations, then the game will eventually crack the 2GB barrier.

In case anyone's interested: With the Process Explorer (an improved Task Manager suppoted by Microsoft), it's possible to see how much address space a process is using, activate the "Virtual Bytes" column. Once the value there goes over 2 GB, the program either crashes (in regular WinXP), or (if WinXP was booted with the /3GB switch, and the program was prepared to use it) continues to operate normally. Note that the actual memory occupied by the process is smaller than the address space it needs. This is also the reason why the regular Task Manager can't be used to check whether a program is in danger of reaching the 2 GB barrier, the Task Manager monitors the wrong variable for that purpose.

Regarding the graphics card: I ended up buying a Sapphire Radeon HD 5670 in the meantime. I wanted to report how it works with the /3GB switch on my mainboard and general environment, but have been so caught up in another project that I didn't try it out yet. Will do so soon though.

 

[Psyringe]

Update: After finishing another project, I finally found the time to test my new graphics card in a setup with the /3GB switch and Civ4. I have the full 3GB of installed RAM at my disposal in the BIOS and in Windows, and I'm having no problems so far. I can even continue the RoM:AND save that I had to abandon due to video memory running out.

 

[Lemon Merchant]

Wonderful!

I'm happy that it worked.

 

[tokala]

Congratulations

Good choice with the 5670. Hopefully there won't be an issue like that if Civ5 gets pushed to its limits by the modding community. Apparently it can come close to the 3GB threshold even without mods, and the x64 version seems to be "delayed indefinately"