GPU question
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16 Jan 2016 22:07:47 UTC
Topic 198380
(moderation:
So I have an old q6600 collecting dust in the basement with no GPU in it. I just upgraded my home machine from a 560ti to a 860, so now I have an extra 560ti laying around. I'm planning on putting it in the extra pc in the basement as a cruncher.
Here is my question since I have no experience with more than one gpu in a machine. Would it be a good idea to buy a second 560ti for cheap to throw in there too? If I don't use SLI, will I crunch twice the amount of WUs?
Second question if the first is possible. Could I buy a 750ti to pair with the 560ti or will that not work? Thanks.
GPU question
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The actual amount that you crunch is depend on the GPU, board, PCIe slot, ram, etc. Some older GPU can be faster than some of the new ones. Yes you can use what ever GPU you want, it's usually easier to go with the same type but you can mix GPU types but will probably need to add a cc_config.xml and a use all gpus command to get mixed configuration to work.
Thanks for the info. I went
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Thanks for the info. I went ahead and threw the 560ti in with my 860. Both are crunching MW units right now.
There are some $100 750ti on newegg right now. Might buy a couple for the Q6600 pc.
RE: Would it be a good idea
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It depends.
Is there a 2nd full length PCI-e slot on the motherboard?
Does your PSU have high enough 12V rating to supply two GPUs?
Have you figured out how you will deal with the heat?
Even if all the above are 'yes', you might be better off using a more power efficient (ie more modern and cooler running) GPU since the savings in power may more than compensate for the extra purchase price. You don't need SLI and the 2nd GPU can even be a different brand.
Probably not - you wont really know until you try. A lot depends on how many lanes each PCI-e slot can access, amongst other things. If you can get x8/x8 for both, you might get reasonably close to the full production from each one. If it's x16/x4, the 2nd slot GPU will probably have a lower production, particularly since boards that supported q6600 CPUs would have been PCI-e V1.x, I believe. To properly support two GPUs, you probably need at least a V2 board. If the board really is V1.x, I would guess you wont be happy with the outcome.
It would work if you have two suitable slots. It would work better in a more modern dual slot board. For GPU crunching, you don't really need an expensive CPU (or a very expensive board). Even a Pentium dual core or an i3 with HT would be able to support both of those GPUs. PCI-e bandwidth is probably the most important factor to keep in mind.
If you intend to crunch BRP6 tasks (Parkes PMPS XT) the beta test app which uses cuda55 will give you about a 25% performance improvement over the default cuda32 app on modern nvidia GPUs like the 750Ti or the 960. If you allow beta test apps in your preferences, you will automatically be given the cuda55 version. I don't think older architectures like the 560Ti would see much (if any) benefit.
Cheers,
Gary.
Some late LGA775 boards
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Some late LGA775 boards (mostly with P45, X38, X48 chipsets) have 2 x PCIe 2.0 x16 and those would run x8/x8, but are designed for CrossFire as far as I remember.
I don't have experience about using dual GPU setup in LGA775 board. Well, about a year ago I experimented with two Nvidia cards (one from 400-series, other from 700-series) in my Asus P45 board, but I remember getting only blank display if both cards were in the slots. I don't know if the result would've been different if both cards had been from the same series or identical. And it might be there was a user error.
The next step, LGA1366 X58... it is a smooth platform to use two cards. Though those boards didn't yet have PCIe 3.0.
This is the board in
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This is the board in question. It does have 2 x PCIe x16 slots.
http://www.newegg.com/Product/Product.aspx?Item=N82E16813131025
Those slots in that board are
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Those slots in that board are either PCIe v1.1 or v1.0.
RE: Those slots in that
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Indeed they are. From what I have seen from doing some searches, a few people have tried putting 600 and 700 series in 1.0 slots with success.
I have one LGA775 board (Asus
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I have one LGA775 board (Asus P5Q Pro) with an E8400 CPU and two GTX 750 Ti's running just great on Einstein. The PCIe slots are X16, running as X8 when two are used (Win7 64-bit). I have been able to mix different types of cards in the past, though haven't tried it with the GTX 750 Ti, but it shouldn't be a problem.
HOWEVER: When you install dual cards of any type (or upgrade the drivers), be sure to do a clean driver uninstall/reinstall. That means using a driver cleaner such as DDU (Display Driver Uninstaller). Otherwise, you will have strange problems. Also, I would not load down the CPU with other projects, but allow one CPU core per GPU.
RE: If you intend to crunch
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In my eyes, the biggest benefit of the beta app is the greatly decreased need for PCIe bandwidth. Basically, PCIe bandwidth doesn't matter anymore. I have a 750ti in a PCIe V2 x4 slot and I see around 1-2% bus interface load using GPU-Z. Even a Titan Black in a PCIe V3 x4 slot has only around 3%. All GPUs are running 2 WUs at a time (yes the Titan Black would need more for perfect utilization). So I would recommend to try the beta app. Even if it does not directly speed things up, the reduced PCIe bandwidth hunger might still help elsewhere. The beta app is also available for the Arecibo GPU tasks if there is work available.
I would throw in the fastest card I can afford (and the PSU can power) and put it in the fastest PCIe slot. The 560ti would be in the remaining slot.
Hi, A related question about
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Hi,
A related question about adding another GPU.
How do you (easily) tell if you are close to or over the capacity of the power supply?
Thanks,
Jay
PS will have to go look at newegg..