P55-UD3R i5/750 HD4850 - what to do with the 4X PCIE slot? CF? Physx?

davidrees

Senior member
Mar 28, 2002
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Current system:

Gigabyte P55-UD3R
i5 / 750 currently stock - soon to do moderate OC
8GB DDR3 1333
HD4850 1GB (Gigabyte fanless)
TT 750W XT (not yet installed)
Cosmo S (adequate cooling and power for second GPU)

So this motherboard has a 16X and a 4X PCIE slot. (only CF is supported, SLI is NOT)

I have seen people using LGA775 systems with this slot configuration do Crossfire using 4850 cards and it seems to scale well - 4X is probably enough bandwidth in most scenarios.

I am trying to decide if it would make sense to add a second 4850 - probably another passive card like the one I have because I am a little obsessed with fanless video cards.

I am curious as to the experience of other people - how would dual 4850s run with 16X and 4X slots?

What if I sold the 4850 and went to a higher level card like a 4890 - will those scale as well in this slot configuration? (in CF)

How would a single 4890 compare to dual 4850s in this system?

I have also wondered about getting a midrange nvidia card for physx processing but I know nvidia is messing with their drivers to try to block this when you use a non nvidia card. I am sure people will continue to hack that so it works with ATI but I don't like to run a platform that is being persecuted by the manufacturers (ie: Snowleopard on a PC, etc)

Of course a 5870 card would be a great single slot solution but price and availability are not on my side right now.

I think I can get a matching fanless 4850 for about 120ish.
 
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lopri

Elite Member
Jul 27, 2002
13,220
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No to the x16/x4 dual-card solution. It's not so much as bandwidth of the slot, but you're also dealing with the DMI and other south bridge stuff (bandwidth contention). It's really not worth the effort, IMO.
 

n7

Elite Member
Jan 4, 2004
21,281
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Yeah i never vote for CF regardless, unless you are going uber high end.

I'd say look into a 4890 or 5850 option perhaps?
 

davidrees

Senior member
Mar 28, 2002
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Thanks for the feedback.

If not Crossfire, is there any other card that can make use of a 4X PCIE slot? Raid Controller or something?
 

deimos3428

Senior member
Mar 6, 2009
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Any PCIe 1x card will fit in that slot as well, so you could add pretty much any peripheral you're missing. (I put a PCIe TV tuner card in mine.)
 

davidrees

Senior member
Mar 28, 2002
431
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What if I replace my 4850 with a high end Nvidia card and then use a mid range Nvidia card for Physx?

It's not a SLI board but shouldn't that not matter if I am using the cards that way?
 

AyashiKaibutsu

Diamond Member
Jan 24, 2004
9,306
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What if I replace my 4850 with a high end Nvidia card and then use a mid range Nvidia card for Physx?

It's not a SLI board but shouldn't that not matter if I am using the cards that way?

I'm kind of planning on trying that once fermi comes out (grabbed a 9800gt for now). I have no idea if it's going to workout well though.