TriFire with Radeon 7990 and 7970

[Damodred]

Hello

I'm about to buy a 7990 from a friend and replace it with my 7970 when I stumbled upon the trifire test here
http://www.hardocp.com/article/2014...5x2_xfx_290x_dd_trifire_review/1#.U45izvmPncQ

So for unknown reasons (,,,) I got interested in trying out trifire with these instead. Will it work the same as with the r290 cards?

Let's pretend it does, would there be a problem if I let my current 7970 stay in the top slot? Seeing as it's cooled with an Arctic Cooling liquid hybrid, its more or less silent and I don't really believe the 7990 is, even in idle.
Would be much better if the 7990 would just shut down when not in use.

Link to arctic cooling system
http://www.arctic.ac/eu_en/accelero-hybrid-7970.html


With some luck I will probably recieve the card before this weekend.

Thanks in advance



Edit:

Oh and while I'm at it - what about the psu?
According to this link the HD7990 will draw only 347 watt at peak and a HD7970 uses 270w. Are these numbers correct? I've seen much higher numbers on other places and are well aware of that watts are still extremely overrated. Quite interesting though as the HD7990 is good for 375 watt while the HD7970 is supposed to stay at 250 watt?

http://www.techpowerup.com/reviews/AMD/HD_7990/23.html

Again, thanks in advance


Edit again, sorry last time:

According to this link the card uses 570 watt. Which in itself is almost 200 watt over specification of the card. How can this be? The PCI-E standard clearly states that two eight-pin connectors should, together with the motherboard I assume, deliver 375 watt.

http://www.tomshardware.com/reviews/radeon-hd-7990-devil13-7970-x2,3329-12.html

Thanks in advance

 

[StangBandito]

I have the setup described.

I have an i5-4670 (stock clocks) an XFX 7970 DD (OC'd to Ghz Clocks) in slot 1 and a 7990 (stock clocks) in slot 2 in Crossfire with one open slot in between them. Powering them is a PC Power and Cooling 950W power supply. Cards are running at PCI-E 3.0 x8.

I have 3 monitors attached to the 7970 and zero on the 7990. I can play pretty much any game with the 7970 but if I need the extra boost turn on 3-way Crossfire. Crysis 3 is amazing at 1440P on Ultra at 60fps.


Whats neat is, with ULPS on, The 7990 stays completely off until I start up the program (game).

The major problem is cooling. running the 7990 alone it cooled fine. Adding the 7970 on top moved the 7990 closer to the power supply and all of a sudden i would get 95+ degrees on GPU2 (GPU farthest to the left on the 7990) I sort of fixed that by buying a new side panel for my Corsair 600T case with space for 4 fans. The top 2 are coolermaster fans the bottom 2 fans are Delta fans which blow directly on the 7990. I keep the Delta fans off (they are really loud) with a fan controller until I need the horsepower

Moving the 7990 to the top position is even worse for cooling for BOTH cards causing all GPU's to overheat and throttle.

I don't want to watercool. My next upgrade is a full tower case. The Corsair 780T is looking pretty sweet but comes out in September.

Ask me any questions, I'll look back here occasionally.

Edit: Run 3 GPU's and you will DEFINITELY need to run MSI Afterburner on a secondary monitor to keep tabs on temps clocks and GPU usage. I do.

 

[Damodred]

Thanks for your reply!

For some reason I always felt the need to put the most powerful card on top and then started to think that such a card is for gaming and gaming only (imho).

I tried the same this weekend and it worked pretty nice! I've got better temps than you do though, the HD7990 peaks at about 75-78 degrees and my hybrid stays at its usual 58 degrees. However I will change how the fans works, the HD7990's fanspeed is extremely noisy at 60%, at 50% I will reach a temp of 90 degrees but its hardly audible.

Have you had any problems with tri-fire? Some say it reduce microstuttering compared to crossfire, but havent noticed any myself.

 

[StangBandito]

Having a 7990 as my secondary GPU is like having a twin turbocharged 5.0 mustang. The 5.0 will get you where you want to go quick, but when those turbos kick in WATCH OUT.

The only issues i have are heat and many games do not work properly in X-fire upon release. But AMD is pretty good with monthly driver updates and it usually gets sorted out. A single 7970 will run most every game maxed out up to 60 fps. Add the 7990 and I pull minimum 100fps on almost everything at 1440p which is nice because of my 100hz overclocked Korean 1440p monitor. Anyone who says there is no noticeable difference between 60 fps and 100fps doesn't know what they are talking about. So smooth.