Watercooled 290x

max40100 · February 21, 2015

I recently installed water blocks on my 2 asus r9 290x's and went ahead and overclocked them. I put a very conservative overclock of 100mhz to bring the clock to 1.1ghz. Since i have done this twice now i have run bench marks and seen values that you would expect from a chromebook. Its fine when i restart the system as the benchmark scores go back to their regular values but i find the sudden drop in performance worrying. There is no overheating or throttling. I just wondered if anyone had any idea what was going on?

Thanks

dadasmithywinkle · February 21, 2015

I recently installed water blocks on my 2 asus r9 290x's and went ahead and overclocked them. I put a very conservative overclock of 100mhz to bring the clock to 1.1ghz. Since i have done this twice now i have run bench marks and seen values that you would expect from a chromebook. Its fine when i restart the system as the benchmark scores go back to their regular values but i find the sudden drop in performance worrying. There is no overheating or throttling. I just wondered if anyone had any idea what was going on?

Thanks

Some chips just dont overclock well. This is refferred to as the "Silicon Lottery". It may be that yours weren't born to be good OC'ers.

cesrai · February 21, 2015

What do you use for OC ??

max40100 · February 21, 2015

MSI afterburner

Najuno · February 21, 2015

For good and high OCs there are some things to consider. First of all get Unigine Heaven 4.0, 3D Mark and Unigine Valley 1.0. Then use a software like MSI Afterburner to tweak the setting of your card(s). Also download GPU-Z in the latest version to monitor the usage of the GPU and the PD and VRAM usage.

A good and sufficient PSU is a necessity for your cards I´d go for a 1000W. Also the CPU needs to be OCed stable that it doesn´t crash or bottleneck your cards in higher OCs. Especially in 1080p benchmarks. It isn´t really hard for me to choke out my cards over my CPU in 1080p and I´ve got a 5960X running.

Now as stated above the so called 'silicon lottery'. The manufacturer has only to guarantee you the specs that a re written on the box. Your chip has a certain ASIC reading, based upon that you can determine the quality of the chip. And the ASIC for a good OCing sample on air is different to the ASIC of a water cooled or LN2 card. But there´s more to it than just the chip. Your memory controller and the quality of the VRAM and of course your VRM. Usually you can live with a lower VRAM OC but if the VRM isn´t high quality, then it´s likely you won´t OC very far.

If you have bought a reference design from AMD it´s likely that you have got Elpida VRAM and a minor quality VRM on the PCB. That was AMD´s biggest failure for Hawaii (XT) cards. The chip itself was an awesome piece of engineering.

And you see that of course very quickly in watercooling because the cards can boost longer and very stable, but never the less, if the VRM isn´t high quality, then cooling isn´t the problem. Of course you benefit from watercooling with cool looks, quiet performance and overall better longterm performance and longevity of the cards, if the loop is big and sufficient enough.

What you see when you OC is probably a driver crash and then it keeps your clock and RAM speeds on a very low level. The only R9 290X that I would run with water cooling would be the MSI Lightning because MSI did an amazing job with these cards, and that´s why they are so pricey in comparison to other R9 290Xs, because they use high quality parts.