Clock speed or more cores? F@h

[RollinLower]

Right, so i tried searching for a thread adressing this, but to my surprise i couldn't find any, nor any answers on the innerwebs!

 

So here's the question: when building a dedicated Folding@Home machine, should i go for more CPU cores (like a Xeon with 8c and 16t) or just opt for a mainstream 'gaming' CPU like a 6700K?

 

I do realise that F@H is very adaptable, but it must prefer one or the other, right?

 

P.s. i'm only thinking about CPU folding here. I know each GPU takes a CPU core, but i just want to focus on CPU folding for now.

Edited October 29, 2016 by RollinLower
typos...

[Imakuni]

38 minutes ago, RollinLower said:

Right, so i tried searching for a thread adressing this, but to my surprise i couldn't find any, nor any answers on the innerwebs!

 

So here's the question: when building a dedicated Folding@Home machine, should i go for more CPU cores (like a Xeon with 8c and 16t) or just opt for a mainstream 'gaming' CPU like a 6700K?

 

I do realise that F@H is very adaptable, but it must prefer one or the other, right?

 

P.s. i'm only thinking about CPU folding here. I know each GPU takes a CPU core, but i just want to focus on CPU folding for now.

Rather, you get an i3 6100 (just to keep Skylake for other things, otherwise you'd go with an older and cheaper CPU) and invest those 300$ you've saved over the 6700k OC setup onto upgrading the GPU to a Gtx 1070, or perhaps getting yourself a second GPU (say, a used Gtx 970).

 

You see, CPU folding is not efficient. If you are just thinking about folding here, you want GPUs, not CPUs. If you wanted your machine to do something else, sure, think of a CPU for that. But if you are thinking of folding alone, forget the CPU and invest all of your cash onto a GPU.

[RollinLower]

29 minutes ago, Imakuni said:

Rather, you get an i3 6100 (just to keep Skylake for other things, otherwise you'd go with an older and cheaper CPU) and invest those 300$ you've saved over the 6700k OC setup onto upgrading the GPU to a Gtx 1070, or perhaps getting yourself a second GPU (say, a used Gtx 970).

 

You see, CPU folding is not efficient. If you are just thinking about folding here, you want GPUs, not CPUs. If you wanted your machine to do something else, sure, think of a CPU for that. But if you are thinking of folding alone, forget the CPU and invest all of your cash onto a GPU.

Alright, so that answers the question why there is no content on the cores vs clocks side of things.

 

So i should just invest in GPU's then. I'll probably go triple SLI 980's, since there's a very good deal on somebody selling those. I'm thinking i should go quadcore for this? Also looking at a used X79 mobo with a cheap Xeon, should be enough to utilize the 980's to the full potential i think.

[Imakuni]

43 minutes ago, RollinLower said:

Alright, so that answers the question why there is no content on the cores vs clocks side of things.

 

So i should just invest in GPU's then. I'll probably go triple SLI 980's, since there's a very good deal on somebody selling those. I'm thinking i should go quadcore for this? Also looking at a used X79 mobo with a cheap Xeon, should be enough to utilize the 980's to the full potential i think.

Rather than 3x SLI 980, get 2x SLI 1070. While upfront cost of a 980 is smaller, power consumption will play a factor in the long term, making 1070 a much better option. Maxwell is efficient, true, but Pascal is much more.

 

As for the CPU, an i3 will do. Due to the way the software works, you don't really need a "core" to feed an Nvidia GPU, you just need a "thread", even if HT; the CPU isn't actually doing much, it's just the driver hogging useless calls that have to be fed with a thread, not with actual usage. If you want to keep the system modern, you can go skylake; otherwise, an older platform will do just as fine.

 

Just be aware of PCIe lane constraints. While you don't exactly need SLI on it's own, I still recommend getting an SLI capable mobo, as those have at least 8x features on 2 slots. Going lower causes a drop in performance. In fact, that's another reason why I recommend 2x 1070 rather than 3x 980: lack of bandwidth / need for a much more expensive motherboard.

[RollinLower]

33 minutes ago, Imakuni said:

Rather than 3x SLI 980, get 2x SLI 1070. While upfront cost of a 980 is smaller, power consumption will play a factor in the long term, making 1070 a much better option. Maxwell is efficient, true, but Pascal is much more.

 

As for the CPU, an i3 will do. Due to the way the software works, you don't really need a "core" to feed an Nvidia GPU, you just need a "thread", even if HT; the CPU isn't actually doing much, it's just the driver hogging useless calls that have to be fed with a thread, not with actual usage. If you want to keep the system modern, you can go skylake; otherwise, an older platform will do just as fine.

 

Just be aware of PCIe lane constraints. While you don't exactly need SLI on it's own, I still recommend getting an SLI capable mobo, as those have at least 8x features on 2 slots. Going lower causes a drop in performance. In fact, that's another reason why I recommend 2x 1070 rather than 3x 980: lack of bandwidth / need for a much more expensive motherboard.

Ah, so that makes a lot of semse actually. I'm still leaning towards the 980's now, since 2 1070's will set me back close to 1000 euro's, while the triple set of 980's is on sale secondhand for about 700 now. I'm still thinking what is should do with the mobo if i go the triple SLI route. The X79 platform gets more and more appealing, since you can get a triple SLI mobo with a cheap Xeon for about the price of a new skylake i3 these days.

 

Anyway, i'm no millionaire, so i'm counting on getting most parts for this build second hand. Which means i'm depending on what people are selling at the moment. I think i might just stretch this project out a bit longer, so i can get the best parts when people sell them.

[porina]

X79 is not cheap last time I tried looking. Maybe consider X99 and a cheap Xeon?

 

On the GPU front, I have another proposal, although will leave it to a folder to work out how its actual performance might work out. I'd suggest cramming in as many 1060 3GB in as possible. You get a decent performance to cost ratio, as well as the energy efficiency of Pascal. In terms of rated flops a 1060 3GB is about 20% down on a 980 though, give or take depending on actual factory OC/boosts.

[RollinLower]

1 hour ago, porina said:

X79 is not cheap last time I tried looking. Maybe consider X99 and a cheap Xeon?

 

On the GPU front, I have another proposal, although will leave it to a folder to work out how its actual performance might work out. I'd suggest cramming in as many 1060 3GB in as possible. You get a decent performance to cost ratio, as well as the energy efficiency of Pascal. In terms of rated flops a 1060 3GB is about 20% down on a 980 though, give or take depending on actual factory OC/boosts.

X79 is wayyy cheaper then X99. X99 is usually priced at 200 euro's for just the mobo, while you can get a good X79 mobo and quad core Xeon CPU for the same price. X79 also features the same 40 pci lanes for multiple gpu scenario's. All other features like nvme and stuff like that really arn't that interesting for a build like this. 

 

The 1060's might be a good alternative tho. I'm planning to put everything into a rackmountable case much like linus's personal rig. So less power consumption might be worth it!

[TheGlenlivet]

If you aren't paying the power bill then the 980s will get you more PPD.  They have a MUCH higher TDP though...  like double!

[SnowyMus]

6 hours ago, porina said:

On the GPU front, I have another proposal, although will leave it to a folder to work out how its actual performance might work out. I'd suggest cramming in as many 1060 3GB in as possible. You get a decent performance to cost ratio, as well as the energy efficiency of Pascal. In terms of rated flops a 1060 3GB is about 20% down on a 980 though, give or take depending on actual factory OC/boosts.

That could work very well. The 1060 3 GBs cost about $200-$210 each when bought new have only a 120 W TDP. On a standard ATX board, you could easily fit three cards in without having to use any sort of riser cable, so around $630 total. You can get some really nice and cheap quad-core Xeons that have remarkably low TDPs, introducing as little heat as possible. These cards also don't take a lot of power, so a 750 W power supply should be plenty.

 

As folding doesn't benefit from SLI (you can't SLI a 1060 anyway), you could also try getting a consumer motherboard and just go with a cheap i5 for about $180-$210, though you'll want a case that can fit 8 expansion slots (the Phanteks Enthoo Pro looks like a good fit), as most consumer motherboards that have three x16 slots only give one expansion slot worth of room to the bottom x16 slot, and most 1060 cards are dual-width. Even if you weren't planning on overclocking the CPU (not much of a point, anyway), I'd personally use a Z87, Z97, or Z170 chipset motherboard, as these chipsets allow you to use the 16 lanes off of the CPU for all three cards, preventing two cards from having to contest the DMI interface's bandwidth.