I just decided to go with a Crossfire setup with my computer.
Here are my specs:
ASUS 99X EVO mobo - latest bios
Gigabyte HD 6850 1GB DDR5 - latest driver
MSI HD 6850 1GB DDR5 - latest driver (2nd GPU)
AMD FX-8350 CPU
Windows 7 Ultimate 64bit
8GB DDR3 Corsair Vengeance
Nothing is overclocked.
I played FC3 with just the gigabyte card and it ran alright. All on ultra, but occasional lag spikes that dropped my fps to 20-25. I decided to get this MSI card. Now the game boots up, plays the game for a few seconds and then kills my computer. It completely restart it. No BSOD. No noise/flicker.
I've checked the temps and they look good.
(CPU at ~36C and GPUs at ~49C)
My PSU is the only thing I can think of that's causing this issue.
I decided to try other graphic intensive games...
Hitman Absolution - Ultra, max AA and shading - solid 50-60fps. No lag whatsoever.
Skyrim - Ultra, Max AA, 59-62 fps. It looks super crisp. Before crossfire, it'd be at about 30-40fps with a much lower AA.
Once I saw that those games played really well...it made me think that the PSU was not the issue.
However, with your experience, what would you say is the culprit?
I feel the biggest issue you face with Far Cry 3 is that it was really designed around the cards that are out now. It is a highly graphic game which many consider to be the most demanding game out on the market right now. Really the DX11 support has really turn ten fold with the current generation of cards and normally games that are demanding like this see a huge turned around with the generation after the game comes out. For example look at BF3 you had your generation of cards the 6000 series and the 500 series from nvidia and both were really pushed to the brink with the game it was demanding and turning up the eye candy came at a price of performance.
Also you are running with 1 gigabyte of ram I would love to see what ram usage the game goes through but I would imagine it probably really pushes beyond that.
I would say I would expect a lot more performance if you were to turn down all AA+AF and see if that helps if not start turning things off like shadows and that I would think would bring your frames up. I just don't see a brand new game which is poised to be a game to bring cards to its knees. If I was to aggressive with what I'm saying I do apologize its my opinion and If I'm wrong I'm sorry.
What brand is your PSU? 850w should be sufficient if it is high quality. Really, 1GB of video memory is not enough for crossfire and the 6850s are not ideal in crossfire anyway. I always recommend buying the single fastest gpu you can afford. BUT, you have what you have, so lets see if we can make it work. Did you download AMD's latest driver? It came out this week. You should probably lower your settings down from Ultra to High at least too. Your temps on the gpus seem awfully low for a full load (49C). I am guessing its not loading both cards. I would run GPUZ and make sure that they are both loading up.
Bigshort: I understand the 6850 is an older card; and I'm in no way offended. What find confusing though is that I was playing FC3 on ultra (AA on 4x) with a steady 30-40fps. Gameplay wasn't an issue, just the cutscenes showed the lack of AA.
hizodge: I've considered running furmark on my system, but I've read so many stories of people running it and ruining their cards. I JUST bought this 2nd card, so don't want to risk it yet. However, if there's a safety cutoff on the test I'll try it.
I confirmed that both cards are being used. Latest AMD catalyst is installed (13.xx). It detects and let's me enable crossfire.
lost: Nope, no burning smell. I thought it was the PSU as well, but not sure.
maestro: I don't recall the brand on the PSU (currently at work, I'll check later though) I know the 6850s aren't the best thing to crossfire, but the card I want (79XX series) is PCI 3, and my mobo just PCI 2.0 I don't want to have to upgrade both the mobo and gpu. I'll try killing the AA once I get home and see if that takes care of. GPU-Z shows both cards in my system.
Also, forgot to mention....the FC3 that I have is the 'non official' version. Can't patch/update the thing because of that. Now I'm wondering if that could be the root of all evil.
Here's another question though: would my system see a considerable improvement with a Radeon 79XX with my current mobo (PCI 2.0)...
Or should I just return the gpu I just bought, and save up for a PCI 3.0 mobo and use a better, single graphics card?
I think its up to you it depends on what you spend on your card. PCI Express 3.0 is a non issue at this point running at 2.0 is just fine. I would say one possibility would be return the card and perhaps get a next gen card when it comes out or possibly a 7000 series card on the cheap your 7950/7970's. I think the extra 6850 that you purchased will only hold you up for a little bit. It's my personal opinion that the next gen cards will have a easy time with the game.
its crossfire. Crossfire is shite. i recently did the same thing as you, went crossfire 6850's, its fine if the fps is high, but if it drops to 40ish fps or lower, you see stutter, and if a game is maxing out your 1gb vram, you see even more stutter, I noticed this most on skyrim with high res texture pack on in a open outdoor area. A month after upgrading to a second 6850 i got sick of it, sold them, and got a better single card. If i were you i'd wouldnt waste my time, return the card, sell your other 6850 on ebay, and go look for a better single card.
Thanks. I've been reading on other's posts about random shutoffs and everyone says drivers or PSU. The more I read about multiple GPU's the better it seems to NOT use them. I read that before I bought it was well; but I figured... I want to get my own opinion.
Looks like this card is going back to tiger.
Thanks for all the replies. Looks like I'll just get a beastly single card and upgrade the MOBO to a PCI 3 down the road.