I pretty much swear by the Accelero Extreme series for quiet cooling of single video cards at this point, but I'm wondering if anyone has any experiences using it for Crossfire/SLI?? The video card and cooler takes up 3 slots, so I'm worried that there won't be enough room for intake air for the fans. I'm planning on using it for both gaming and mining, so the combined power load and resulting heat will be pretty high. Alternatives would be to get a couple of radial blower design cards (which I have no experience with) or an OEM design like the AE, but which only takes up 2 slots. The R9 290 Tri-X got a rave review from Anandtech, but Anand is no MikeC http://anandtech.com/show/7601/sapphire ... cooled-290 .

Anyone have any thoughts? Should I just get regular R9 290s and acceleros for both? Any other GPU cooling solutions I should be looking at?

I'll only be getting two cards by the way, which limits the thermal load.

EDIT: I just realized that 2x Acceleros would not be possible - they won't fit in the case. Same goes for the Tri-X. Guess I'll have to look into a new case and PSU now too (Antec P182 and CP850 currently).

For me its all about single cards, once going into or considering SLI i would give serious though to watercooling. I personally im considering it for going in the future with SLI and driving a 4k monitor, but still is something that i fear in terms of noise, today there are rads design for low airflow even fans that can be driven very low, the only thing that worries me is the pump, but there are some solutions there.

If you still want to try out AIR on Xfire R9 290X, then i would probably wait for MSI twin frozr edition, but its going to be a lot of heat dumped inside the case, you will probably going to need much higher rpm on the case fans to deal with this. Now the 290X on stock blower... all the reviews that i seen they say it get extremely hot and noisy, so i wouldn't consider those as a solution.

More non-reference cards are coming. Guru3D reviewed the Asus CUII version and had similar results to Anandtech with the Sapphire card. Might as well wait a bit and see how they pan out. Then decide which way to jump. Either way, you'll need some decent case ventilation and unobstructed airflow for both cards.

Water cooling adds pump noise, and turbulence noise from cooling the radiator. The only way it makes sense IMO is if you have radiator with a big enough surface area that you can cool it passively outside the case. Otherwise you're just shifting heat around inside the case. They also don't cool the VRMs as good as an air cooler. I suppose there is a minor advantage to having it inside the case in that if airflow is restricted because the cards are sitting too close to each other, moving the heat to another part would make it easier to cool with regular case air flow.

Computerbase.de did a test of the Tri-X, and it gets the same noise performance of a Accelero at 12 V (German, but you can look at the figures):

http://www.computerbase.de/artikel/graf ... im-test/4/
http://www.computerbase.de/artikel/graf ... m-test/10/

At 7V the Accelero wins hands down again. I'd be using the cards with the Accelero hooked up to the video card however, which gives a variable fan speed, and presumably better acoustics than maxing it out at 12 V. The issue is whether the cards being next to each other would impede the incoming airflow to the Accelero enough that it makes sense to go for a Tri-X solution instead, which would leave an extra slot between each card. The price is the same, so it's really a question of what works best.

By the way, I'm not considering the 290X at this point, only 290. The 290X is too expensive and doesn't provide enough of a performance boost to justify the cost, or heat. Oh, and the CUII did far worse than the Tri-X at ComptuerBase, though I guess that's expected given it's a 290X.

Define "next to each other" in cm. Is it zero? 1cm, 2cm, more? If they butt up against other, you will be guaranteed to starve the card of air.

Is there a 3rd x8 PCIe 3.0 slot that's farther way? You could use that instead and not impact fps.

I figure about 1 cm clearing to the actual fan blades - the Accelero has fan guards that stick out slightly to prevent anything adjacent from coming into contact with them. I can't move the card positions due to the slot configuration on the motherboard, at least not without getting a new motherboard with a different layout.

I think 1cm will starve the cooler. If it were me, I'd find the lowest noise aftermarket cards and try those first. Then, if you can't stand it, retrofit. Then, see if you need a new mobo with decent PCIe spacing.

That would be the Tri-X, so far at least. Problem is the price premium - for what the card costs, I could get a reference board and Accelero.

Yep...and then get a new mobo to support cool SLI support

Your call.

Heh, the mobo is only 2 months old. My requirements just changed a lot faster than I thought they would. Thanks for the advice and perspective - next I'll be researching cases, case fans and PSUs. Hopefully that should help narrow things down, and give me a better overview of the total budget.

Have fun

By the way, the next gen Nvidia cards might be out in the first quarter. 20nm should kick up the performance/watt a bit.

I kinda think they might wait for Intel to release broadwell that should be like mid year, i think they are comfortable as they are atm with the their line, but im really curious into how better the GTX880 will be, or if Nvidia will follow the trend of a TITAN 2 early.

I'm sure the performance per watt will be good for gaming, but for mining alt coins (litecoin, dogecoin etc.), Nvidia has a huge performance gap compared to AMD. A 780 Ti can achieve 430 kh/s, compared to the 630 kh/s I'm getting on my 7950 - a R9 290 (non-X) should be able to get 800 kh/s. I'm not sure whether the problem is due to architecture or coding optimization (probably a little of both), but they have a huge gap that's going to take a lot to fill. Add to that the new CrossFire and better multi-monitor support, and AMD is the right tool for the right job for me at this point. I wish it wasn't like that, as cooler and quieter would have been a lot nicer.

The GPGPU gap is due to architecture - Nvidia took a left turn with Fermi. We really can't pre-judge what Maxwell can do. That said, have fun with whatever you choose to do.

IME, with about 3mm between my SLI setup, an Accelero will not workout for you. They will be starved for air and with a GPU as hot as the r9 290 you are sure to run into throttling issues and the like. Most SLI/Crossfire owners suggest blower coolers, but this will obviously not suffice either as they are super loud, particularly AMD's reference design, which is more or less the only blower available.

I started with a blower, then tried the Accelero, and then eventually modded my cards with Kuhler 620s to get close to quiet. Unfortunately, with high-end GPUs in a multi-GPU setup there really is no choice but water if noise is a concern. So, I'd like to offer some clarification:
While this is true, a modern pump with a custom top can be very, very quiet, inline with <700rpm fans. There are multiple threads here in the watercooling forum and many tests at Martin's Liquid Lab - pumps are not as loud as they used to be and can be dialed down and dampened to the point where a quiet fan at low speeds will be louder.
This is true, but not a concern in a decent case, and also not very different from fans pushing air through a heatsink. With the decrease in temperatures you get from watercooling you need significantly less air to keep things cool. If your case has provisions for 3x120mm radiator (whether it's 1x360 or 1x 240 and 1x 120), you can get away with very low FPI radiators and low RPM fans to ameliorate any "extra" turbulence you might observe when compared to an air setup.
This is the biggest justification for blower coolers in a multi-GPU setup. Most aftermarket cards and coolers push air out from the card and into the case, and with a second card cm's away, onto the second card, significantly increasing system and especially GPU temperatures. Blower coolers relieve this by exhausting the air outside of the case, but with the premium of a lot of noise from a) the radial fan and b) the radial fan having to push air through a very high FPI heatsink, and sometimes a vapor chamber.

While this is still an issue with watercooling, your 2x r9 290s won't be running at 94* on load, they'll be closer to 45*, making for much less heat, and rather than hot air being pushed around awkwardly over your PCI slots, you can arrange your radiators to ensure proper airflow for your case as most users mount their radiators on a case's intake or exhaust.
I am not sure where you heard this but this is only true if you are using a universal GPU waterblock. Most users with high-end cards opt for full cover blocks, which will cool VRMs significantly better than any air cooler could hope to. This can be verified in any r9 290/x owner's thread on any enthusiast forum - users on air, even with nice aftermarket coolers, have VRMs pushing 90* on load while their GPU is less than 80* (this is true of Tri-X and Accelero). Users with a full cover block have core temperatures in the 40's and VRMs in the 60's.

Anyway, I'm not trying to convince you that your only option is water, and I have my own hesitations around watercooling (cost, setup, maintenance, cost), but, generally speaking, with multi-GPU setups it is the quietest and best performing option.

Thanks for your thoughts claes. I got a second cheap 7950 (dual fan) to do some mining and testing with my current setup, and the case can't handle the extra heat properly at default voltage and clock speed. I have to underclock and downvolt slightly to keep the system stable. While I was going to get a new case anyway, having experienced this with 2x 200 W, I can only imagine how bad it's going to be with 2x 300 W. The Accelero actually handled the heat itself "fine" but the fan speeds got more and more into sound levels I wouldn't call acceptable.

Do you have any thoughts about the Accelero Hybrid? http://www.arctic.ac/eu_en/products/coo ... ybrid.html

Any other alternatives I should be looking at?

The Accelero Hybrid is out looks like, as delivery isn't until mid-February. I can't wait that long. There's a local store that sells WC kits and gear, so I'll be stopping by them to get a proper build setup.

Got everything setup, and this is definitely noisier than I was hoping for. The radiator fans are the main culprit, as they need to run at a certain rpm to actually push enough air through the radiators. The pump is also quite audible. I'll have to try some tweaking of rpms and voltages to bring the noise down, but due to instability issues I'm not sure how much I can push this.

Knowing what I know now, I can't really recommend this path - the 290(x) cards are simply broken temperature wise with how they ramp up and dump heat everywhere. Anyone looking into scrypt mining is far better served by the 280x (7970 rebadged) - it has only 100 kh/s less and can be tweaked to close the performance gap, and is far more efficient. For gaming, two of them in crossfire should last you at least 4 years and then some.

I'm not sure if I'll do this again come the next setup - the price of water blocks for the gpus is very high, and it really only makes sense if the cards are thermally limited in some way (like the 290(x)).

That is unfortunate, sorry to hear, and sorry to take so long in responding. Had I responded earlier I would have said something like:

The Accelero Hybrid and "the Mod" are good options, but the 290/x is an incredibly hot card, and it's unlikely that a heatsink and a single fan would be enough to keep the VRMs in check. Moreover, in crossfire you're talking about 2 pumps that are noisier than custom pumps and certainly noisier than low-speed fans.

Now that you have built your loop I'm wondering:
What pump are you using? Is it hard or soft mounted?
What kind of radiator are you using?
What kind of fans are you using?

I went with an Ek setup, plus Obsidian 900D case. Single EK-DDC 3.2 PWM pump, two XTX 360 radiators (64 mm thick), fans are Noctua NF-S12A FLX at 900 rpm. I was advised to grab a cpu block as well, so added that too (cpu is only a fraction of the thermal load, and the megahalem I had before would make it harder to route the tubing anyway). Pic:

https://www.dropbox.com/s/16yubzyqymfn1 ... ooling.JPG

The pump is mounted using a anti-vibration bracket. I don't remember the part number right now.

I don't know if you're keeping the loop, but you might try decoupling your pump by suspending it or putting it on thick foam, it makes a significant difference when compared to a hard-mount situation.

You might also try different fans - while NF-S12s are quiet, but they aren't exactly great for airflow through a radiator, particularly when you look to CFM/db. Gentle Typhoons, SilentWings, Scythe, or F12s or P12s might better serve your needs.

I had a pretty limited fan selection, so had to go with the best of what they had. That site you linked, didn't test the Noctua S12A, only the S12B. Considering the S12A actually replaces the B (strange, I know) the results should hopefully be about the same, and in that case the fan is actually quite good according to that link. The Gentle Typhoon ones are the only ones that might make sense from an upgrading perspective, but they have worse subjective sound characteristics, so it would be a difficult choice.

I am not sure if you're concerned, but I think you're reading the chart incorrectly. Although I'm not sure if the s12b and s12a are comparable, I do know that both are slow spinning case fans that don't direct air that well and create very little pressure.

If you look at the "radiator noise" section you'll notice that the s12b achieves a maximum of 25 cfm at 46db, which is pretty loud for the performance. Comparatively, a GT15 can push 35 cfm at 45db, or 10 more cfm at the same db. If you only need 25 cfm, they'll do it at ~39db, or 7db less than the s12b for the same performance on a radiator.

As far as "subjective noise" is concerned I think you'll find anything above 7 to be great at 2m and should look to the resonance column for problem fans. Subjective noise refers to motor noise which will be negligible with a "quiet" fan from more than 1m in a chassis.

SPCR's review of the GT.

That's at max speed - I'm running them at 900 RPM. The case is next to my desk, so 50 cm, not 1-2 m. Noise characteristics at that distance is definitely a possible issue, and for that the S12A should be superior. What I hear right now is turbulence noise from the fans blowing on the radiator, not the fans themselves, so it's a question of thermal performance vs. turbulence. The fans themselves are not the problem - necessary static pressure and radiator design is.