Nvidia PhysX "Sli" performance question

[Hanzo]

I'm just getting the final details of my new build together, I was planning on getting the 1GB ASUS 4850 from Scan but I have just been offered an Geforce 8400GS for £15 and after reading around a bit about the application of PhysX on multiple Nvidia GPU's I am a bit torn.

I've always had Nvidia cards in my systems and I am very tempted to stick with them as a GPU and pick up the XFX 9800 GTX+ for the same price as the 4850 ASUS is, but also to pair the 9800 with the 8400GS so that the 8400 GS runs PhysX.

I know since they don't technically run in SLI I won't need to change my motherboard (I have a crossfire compatible board picked out).

My question is whether the 8400GS will be able to run the PhysX processing acceptably well when paired with the 9800GTX+. I play quite a bit of UT3 so I know I'll see some benefit from getting PhysX running.

Does anyone know whether the GPU type running PhysX has a huge affect on performance? Or are all the 8000 series GPU's and up beefy enough to run PhysX well?

[Lee H]

Hanzo

If you drop a post in the scan forum and we'll look into this as the 8400GS is an entry level card and is not really designed for SLI usage.

If you can pop your invoice number on there, I can hide that field and then check to see what other viable alternatives we have.

Best Regards,

[kalniel]

Lee, he's not going to use the 8400 for SLI at all. The enquiry is just whether you can do any meaningful PhysX on the 8400 when used as an additional card.

My feeling is that even if PhysX can be enabled on the 8400, it'll be so slow as to be worthless.

[Hanzo]

Well it's not really running in SLI, it's Multi GPU Mode. I saw tests run here ---> firingsquad.com/hardware/nvidia_geforce_physx_performance/page8.asp and thought that the very cheap but not useless 8400 might be good running PhysX by itself with the 9800 handling graphics.

I don't have any experience with Nvidia's PhysX software or Multi GPU set ups but thought this sounded like a fairly cost effective way of getting a nice performance increase.

[edit]kalniel: I know the 8400 can run PhysX, at least Nvidia's website says it can.

Are there any tests that show the PhysX performance of different cards running in Multi GPU mode?[/edit]

[kalniel]

If you have a 9600GT level card or better doing the PhysX, yes.

[Lee H]

I've searched the web for 8400 physx and found some information regarding it's performance.

8400GS running GPU PhysX is about 10% faster than a stock speed Q6600 running software PhysX

taken from the following link ;

http://www.hardforum.com/showthread.php?p=1032891756

I hope this information helps.

[!TIMMY!]

I totally did not realise that you can do this on a non SLI mobo! I am going to shop around for a cheap 8 series card!

[moogle]

I totally did not realise that you can do this on a non SLI mobo! I am going to shop around for a cheap 8 series card!

News to me!
Pretty good but what about ATI setups?