Want to go CFX - suggestions please...

[railven]

I currently have a launch ref Sapph 7970 which I run at 1125/1575 @ stock volts.

System:
i5 2500k @ 4.4ghz
2x4GB RAM
Corsair 850W

First question:
Whats the performance penalty for going HD 7970+7950? Just asking, seeing if I can cheap out a tad :awe:

Otherwise, looking at these two cards, which would you recommend:
GIGABYTE GV-R797OC-3GD Radeon HD 7970 3GB 384-bit GDDR5 PCI Express 3.0 x16 HDCP Ready CrossFireX Support Video Card
http://www.newegg.com/Product/Produc...82E16814125413
vs
SAPPHIRE 100351SR Radeon HD 7970 3GB 384-bit GDDR5 PCI Express 3.0 x16 HDCP Ready CrossFireX Support Video Card OC with Boost
http://www.newegg.com/Product/Produc...82E16814202008

I'm leaning more towards the Sapph since my current card is one, which I'm sure doesn't matter.

Either way, any feedback on which is better? Thanks in advance.

 

[OVerLoRDI]

What resolution? What games are struggles for your current system?

 

[ICDP]

The Gigabyte WF 7970s (and 7950s now) are voltage locked. Avoid them.

Not sure about the Sapphire one but it should still be unlocked for voltage control.

Going to a HD 7970/7950 setup should yield a nice increase, just make sure your 7950 can run at decent clocks to keep up.

 

[railven]

What resolution? What games are struggles for your current system?

Tomb Raider and Crysis 3 I know will struggle on one card with max settings and any kind of AA.

Also 1440p@60hz and on occassions 1080p@120hz

The Gigabyte WF 7970s (and 7950s now) are voltage locked. Avoid them.

Not sure about the Sapphire one but it should still be unlocked for voltage control.

Well that's good to know. I tend to not overvolt up, but if by volt locked you mean I can't down volt either, perhaps I'll completely avoid that card. It has a similar looking cooler to my current Accelero but that won't matter since I won't see it haha.

Going to a HD 7970/7950 setup should yield a nice increase, just make sure your 7950 can run at decent clocks to keep up.

I'm trying to find a decent article/review that covers hybrid CF. For example, would the microstutter be worse? (I also plan on using frame limiter when possible.)

The cost difference is something to consider if the performance difference is less, and more importantly the penalties (microstutter, conflicts) are the same. I would assume CF regarldess of 1:1 or hybrid have the same issues once both cards are set to identical clocks. But I haven't CF/SLI in over 4 years

 

[wand3r3r]

I haven't seen any reviews of HD 7970 + 7950 in crossfire but personally I'd probably go that route, considering the 7950 starts at $280-300 for the voltage unlocked ones (sapphire/msi) and the 7970 is about $400ish.

Considering the 7950 is only ~5-10% slower clock for clock I'd overclock them both (hopefully to about 1150 or so) and give it a go with a frame limiter or radeonpro. Basically you'd sacrifice the slight clock for clock benefit of the 7970 but also save $100 or so. There's always the risk it doesn't play the way you want so there's less to lose with the 7950.

I haven't heard about that exact combination though, only that theoretically it's possible.

The one other thing that I'm wondering about is that the frame times appeared to be a little smoother on the 7970 than the 7950 iirc (should dig up a source), which is probably why tr chose the 7950 vs. 660 ti.

 

[Dravonic]

You should really, I mean REALLY, find some review or at least some user experience with hybrid CFX. Remember that AFR means one card renders a frame, then the other one renders the next. A slower card could very well screw up with your frametimes. CFX already has microstuttering problems as it is.

 

[railven]

You should really, I mean REALLY, find some review or at least some user experience with hybrid CFX. Remember that AFR means one card renders a frame, then the other one renders the next. A slower card could very well screw up with your frametimes. CFX already has microstuttering problems as it is.

Yeah, that's exactly why I was asking. I'm still looking into cards, wish my Microcenter sold 7970s so I could pick one up and just start tinkering.

Possibly gonna order the Sapph tomorrow so I can have it for my long weekend

 

[aaksheytalwar]

1. I would not purchase cf in the current situation.

2. Even if I did, I wouldn't be adventurous enough to go with hybrid cf.

3. The $100 saving is also not worth it IMO considering you have already bought the first 7970. I would just buy the same 7970 again if you really want to do cf that badly.

 

[railven]

1. I would not purchase cf in the current situation.

2. Even if I did, I wouldn't be adventurous enough to go with hybrid cf.

3. The $100 saving is also not worth it IMO considering you have already bought the first 7970. I would just buy the same 7970 again if you really want to do cf that badly.

1) Why not? Because of possible refreshes?

2) Yeah, not finding enough info to go hybrid, figured I'd ask.

3) By same do you mean same model? Or same as in getting the 7970 again?

 

[aaksheytalwar]

1. Too much MS, other issues and negative publicity.

2. Ya

3. Exact same model. Perhaps that may reduce frame times to a limit. Though I have nothing to back this hunch.

 

[railven]

1. Too much MS, other issues and negative publicity.

2. Ya

3. Exact same model. Perhaps that may reduce frame times to a limit. Though I have nothing to back this hunch.

1) Why I wish Microcenter had the cards locally so I could test for myself and eat restocking fee if unsatisfied. I was going to use Frame limiter either way. Publicity doesn't affect me.

3) I don't even think they sell my exact model anymore, it was a ref sapph.

 

[chimaxi83]

You don't need the same model. Just match 7970 to 7970, and clock speeds, and they will function the same regardless of brand.

 

[railven]

You don't need the same model. Just match 7970 to 7970, and clock speeds, and they will function the same regardless of brand.

I figured that - twas going to be my intention, but just noticed some of the 7970's come with Boost now?

I think the Sapph I linked above doesn't have boost though.

 

[ICDP]

1. Too much MS, other issues and negative publicity.

2. Ya

3. Exact same model. Perhaps that may reduce frame times to a limit. Though I have nothing to back this hunch.

I would always advocate SLI over CF because it is easier to work with and in works better out of the box. But the too much micro stutter line in CF is mainly hype by websites that don't do what most other gamers do, ie use vsync, triple buffering or even FPS limiters.

Here are a couple of frame-time graphs taken using 2x HD 7950s in CF (separate vendors) from two recent games releases. I use RadeonPro to set vsync and triple buffering on and also set link FPS to monitors refresh.

2560x1600
HD 7950s in CF @ 1100/1450

Tomb Raider
Ultra setting but with shadows set to Ultra (they are high in Ultra preset). DOF off

The high spike at around 12 seconds was caused when I was close to Lara while she climbed an obstacle. TressFX in close up

Hitman Absolution (this was taken with both 7950s at 1000/1450)
Ultra setting, 2x MSAA, Bloom off and DOF off.

 

[railven]

I would always advocate SLI over CF because it is easier to work with and in works better out of the box. But the too much micro stutter line in CF is mainly hype by websites that don't do what most other gamers do, ie use vsync, triple buffering or even FPS limiters.

Here are a couple of frame-time graphs taken using 2x HD 7950s in CF (separate vendors) from two recent games releases. I use RadeonPro to set vsync and triple buffering on and also set link FPS to monitors refresh.

2560x1600
HD 7950s in CF @ 1100/1450

Tomb Raider
Ultra setting but with shadows set to Ultra (they are high in Ultra preset). DOF off

The high spike at around 12 seconds was caused when I was close to Lara while she climbed an obstacle. TressFX in close up

Hitman Absolution
Ultra setting, 2x MSAA, Bloom off and DOF off.

I always prefer to judge for myself as I don't tow any company lines like some of our posters.

If CFX is as broken as it is claimed to be, I will slam it and never recommend it, however, if it works reasonably well I'll try to share my experience.

I only have one game that has had the microstutter issue on a single card, which is WoW, but I honestly only notice it when I'm looking for it or just idly staring at my screen, never during combat/action.

 

[railven]

So, it turns out I've been wrong on my PSU this whole time. Was double checking before I placed my order and realized I have a Corsair 750W TX ver1. Woof.

Here are the complete systems as far as I can tell from memory:
Intel i5 2500k @ 4.4 - 1.3v
Saphh Radeon w/Accelero Extreme @ 1125/1575 @ 1.175v
1x128GB Vertex 4 SSD
1x500GB Seagate 7200.12 HDD
2x140MM Corsair AF120s with volt reducer (for less noise, thus less power draw.)
2x120 Corsair SP120s with volt reducer (for less noise, thus less power)
1x200MM Corsair fan (running low)
2x120MM Corsair fan (running low)
[Top 3 fans are the stock fans on the Corsair Carbide 500R, I run on the low setting from the front panel control switch.)
Corsair H60 HSF
1xLogitech KB
1xLogitech Mouse

So, with that all listed, you think 750W would be enough for a second Radeon? Chances are I'd probably run both stock to avoid any hiccups since I use v-sync 90% of the time.

Thanks in advance.

 

[UNhooked]

I believe that is made by Seasonic, if so then you are fine. However I would be a tad bit careful when overclocking since the power requirements increase considerably

I too am running my entire setup including the watercooling on a Seasonic built PSU

 

[railven]

I believe that is made by Seasonic, if so then you are fine. However I would be a tad bit careful when overclocking since the power requirements increase considerably

I too am running my entire setup including the watercooling on a Seasonic built PSU

Reading over your sig...what are your 7970's volts at?

Seems like I shouldn't have much of a problem. That's reassuring.

 

[UNhooked]

Both my cards are running at stock speeds since I only game at 1920 X 1200. One of my cards runs at 1.056 and the other at 1.176.

The one that runs at lower volts is made by Diamond and has an ASIC quality of 85% I think. The one that takes more volts is made by XFX and has a weak ASIC of 67%. Both of them OC to GHZ speeds on stock volts. Also both run like champs when flashed with the Ghz Bios, however that shoots up my power wattage considerably.

So unless I really need my system to run beyond 40FPS in any game, I am going to keep it at my current levels. Down the road I do plan to get a 30inch monitor running at 2560X1600 so I'll take a look the clock levels then.

Update: Also both my cards produce coil whine. The Diamond has come down a bit considerably but the XFX continues to do it. However setting the game to cap at 60FPS and Vsync etc help with this. And since I am not aiming to break any world records, these settings work for me.

 

[Bill Brasky]

I believe that is made by Seasonic, if so then you are fine. However I would be a tad bit careful when overclocking since the power requirements increase considerably

I too am running my entire setup including the watercooling on a Seasonic built PSU

Actually v1 was made by CWT, while v2 is a seasonic build. Just FYI.

 

[UNhooked]

I believe you are correct. I stand corrected