Help understanding SLI, Cross fire and OC

[Networker4321]

I am building machines for folding. Mosr recently bought all the components to build what I thought would be a decent folder.

Windows Pro (SP3) 2002, Gigabyte mobo GA-EP45-P45, Rosewill 1000 watt PSU, 4gb OZR mem (2x2 DIMMS), Intel E7500 Core 2 Duo 2.93Ghz, DVD.CR-RW, Sata WD3200 320GB, 7 fans, nvidia GTX295 duo.

Other than Fur and CPUz, nothing else loaded.

Recently bought an nvidia GTS250 and have a spare ATI Radeon 4890. I thought it would fit in the 8 bit slot and it did, had to reslot the 4 port USB to get to the 8 bit slot. I thought at first I had a hard failure after installing the 4890,machine would not power on. Take out 4890, look around, discover I had completely dislodged the wire for the power switch.

I am told by the folding forum to enable SLI, how do I do that? Don't see an option in the nvidia control panel. I ran CPUz and posted the 4 first tabs in PHOT0S under Networker 4321. Shy was a big help, as always over in the graphics card area.

Thought I would look at the cross fire film cable with 90 degree connectors but they do not line up and I honestly dont know they do for me.

Last but not least, I need a beginners guide to OC'ing. Nothing drastic though I am willing to futz around with small, incremental voltage inreases if that's part of the recommendation.

Will the addition of the 4890 with a bit of OC on both cards help my PPD output? I currently rank as 14th, be 13th by Monday or Tuesday.

Thanks everyone.

[RicheemxX]

I'll only be able to answer a few questions here as I'm not totally sure I even understand what you are going. But SLI and Crossfire or not interchangeable terms, sure they meaning running two cards together but SLI is for two identical (series wise) NVIDIA cards while Crossfire is for two Crossfire compatible ATI cards. Unless you are running lucid logic's hydra chips you can't mix and match the two and run the cards bridged togather.

When Shy was talking about enabling SLI he meant on the single GTX 295 since its essentially two GTX 200 series cards in one. I' not really sure about dual board cards like this but I'm assuming that's what he meant. Since you added a second GPU I'm not sure you get the SLI option for the single card.

I need a beginners guide to OC'ing

Google it man, I'm sure there are several out there. Its just like OC'ing anything else you look at some results others have achieved as a baseline then start by making small bumps. Watch your temps and go from there.

Will the addition of the 4890 with a bit of OC on both cards help my PPD output

That's a pretty silly question, of course it will.

[Networker4321]

I'll only be able to answer a few questions here as I'm not totally sure I even understand what you are going. But SLI and Crossfire or not interchangeable terms, sure they meaning running two cards together but SLI is for two identical (series wise) NVIDIA cards while Crossfire is for two Crossfire compatible ATI cards. Unless you are running lucid logic's hydra chips you can't mix and match the two and run the cards bridged togather.

When Shy was talking about enabling SLI he meant on the single GTX 295 since its essentially two GTX 200 series cards in one. I' not really sure about dual board cards like this but I'm assuming that's what he meant. Since you added a second GPU I'm not sure you get the SLI option for the single card.


Google it man, I'm sure there are several out there. Its just like OC'ing anything else you look at some results others have achieved as a baseline then start by making small bumps. Watch your temps and go from there.



That's a pretty silly question, of course it will.

I am going to stick with the single 395 and bencmark it first, THEN, I will add the 4890 and benchmark again.

I will google for beginner pointers on OC'ing.

Thanks for the response, it helps give me some instruction!

[ShyguyXPC]

as I said in your other thread, and as Rich has pointed out, SLI and Crossfire will not MIX, only Lucid's Hydra Chip will do this, and those are on $400 motherboards.


but I need to correct you on some things in the opening post first.

Its NOT an 8 bit slot, is an x16 PCI Express Slot running at x8 Bandwidth.

if it were an 8-bit slot, there's no way even a 15+ year old PCI card would run on that, you'd be talking about a slot with 1 quarter the bit rate of PCI.


if others read your post, they won't have a clue what your referring to.


as Rich pointed out, yes, thats what I was saying about SLI in the other thread, since you have a Dual GPU card, its an Nvidia Card, and Its 2 GPU's in SLI on one card. I haven't seen my self personally, what the drivers display for options, but from what I gather, there should of been an option for enabling or disabling SLI, to allow one or both cards/GPUs on the single card to run.

No where did I ever say running a 4890 with the GTX 295 and enabling SLI (or even Crossfire for that matter) for them.


honestly, with the issues you've been having, especially with mixing of GPU's.

I'd take that GTS 250 card, and pair it up with the GTX 295, and swap that Radeon 4890 in to the other PC that currently has the GTS 250.

at least this way, all of your Nvidia Cards are in one rig, and ATI in another. you only have to install Nvidia Drivers for GPU's on one machine, ATI on the other, instead of mixing them, which will cause less headaches down the road.

you WILL NOT be able to SLI the GTX 295 to the GTS 250, so don't even try.

but you will be able to run both cards together.

you should be able to net nearly 20,000 PPD just from those 2 cards, Overclock them a bit if you can, and maybe eek out a few thousand more points.


just keep in mind, at least on Nvidia cards, overclocking the Shader Clocks 1st, Core 2nd, and Memory 3rd, should net you the best PPD ratings.

on ATI cards if I remember right, the Shader and Core clocks are Linked, and you'll have to increase them together, with only memory clocks separate.

for Folding, its the Shader and Core clocks that make the biggest difference in Folding Performance.




Just forget about Crossfire and SLI altogether when it comes to Folding, unless there's some big magical improvements in GPU3 client when that comes out, for now though, forget about it.

You'll need to run each GPU separately.

for the Nvidia Cards, this is why I suggest running all the Nvidia cards under one rig, as you shouldn't need any Dummy Plugs to get the other cards to show up and fold.

for the ATI card, unless its the Primary Display card in the PC, you may need a Dummy plug or a 2nd Monitor connected to it, to get it to show up and fold.

this tends to be the case when using a GPU folding rig with more than one ATI card as well.




So for plan of attach, if it were me, I'd run all the Nvidia Cards (GTX 295 and GTS 250) in one rig, and Radeon 4890 by itself in the other rig.

one set of Brand of Video drivers per rig (Nvidia for Nvidia, ATI for ATI), no mixing of Display drivers, less hassle and confusion, no need for Dummy Plugs or 2nd Monitor connections also equals less hassle.

as it is I have a 3 x16 Slot PCI Express motherboard for my GPU folder, and only 2 Nvidia GPU's on it, I have a 3rd, but its a low end GT 220.

I've thought of running my Radeon 4870, but its a bit of a hassle with the dummy plugs, arrangement of cards, driver mixing, etc.

I was looking to sell the Radeon 4870, which I'm still up to doing, but was going to see about even trading for a GTX 260 or comparable Nvidia Card, but now I'm thinking of Selling or Trading for Socket 775 Core 2 Quad Q6600 or Equivalent if I can, or even a Core i3 530 (2.93GHz, Hyper Threaded, VT support).

as I'm finding out I want a nice Dual core with HT or Quad core to run as a Network Render Node for my 3D graphics software, to help my current i7 quad.

would also work nicely for SMP Folding as well. they have some nice Open Box Socket 1156 boards for around $50-75 on newegg, H55 chipset boards, that I could spring for if I got an i3 on trade.

but more likely I'll sell the 4870 and then just buy one of these CPU's.

which means I'll be running all Nvidia GPU's on my GPU folder, two 9600 GSO's and a GT 220. should give me a decent 7000-8000 PPD rating at least.

Overclock the 1.6GHz Pentium Dual Core, and see if I can't get a decent 1000-2000 PPD rating on SMP with that (not talking Big jobs for SMP, just regular SMP)

I wish my Mini ITX plans had panned out for Folding, but that rig will remain a basic use low low end gaming PC, with the 2.4GHz Celeron Dual core in it. since it has an onboard Geforce 7025/7050 GPU, which isn't capable of Folding anyways.