Quote Originally Posted by tiborrr View Post
Today I quickly ran our GTX Titan card and the highest delta I saw was about 8.5-9?C (D5 on setting 1) or about 6.5-7?C (D5 on setting 5). The loops consists of a single 360 rad and a D5 X-RES system. Even if the block contact was less than perfect one would suspect the higher mass flow cannot solve this. Therefore, a delta of 2K should be expected but not the delta of 10K.

Because the BIOS is still the stock one I could overclock it by +150 / +450 / 106% (GPU/RAM/Power limit respectively). If you send it to me (via email) I can try to replicate the results on Monday.

What I find odd is:
1. EK-FC Titan scaling so well with high flow rates. Usually, low-restriction water blocks like ours do not gain much with higher flow rates. On the contrary, blocks with exceptionally narrow micro-channel structure (e.g. Koolance, Aquacomputer) react positively performance-wise to higher flow rates. It is simple logic really - the more surface area, the bigger the effect. I believe there is a problem with (consistent) throttling of your GTX Titan or maybe with the thread lenght on your fittings? The fitting thread lenght should NOT be longer than 5mm. See this picture: http://i.imgur.com/PjBi23mh.jpg
2. XSPC block is way off the charts. It has the smallest cooling engine of them all therefore it should perform even worse with larger heat loads (given the contact is okay with all of the tested water blocks).
3. Every block you test it performs better. 10?C on a VRM is a too big of a margin given the fact both XSPC & Aquacomputer blocks have direct contact with VRMs. Where and by using what methodology (IR, wire sensor, foil sensor) is that measurement taken?- NEVERMIND I RE-READ YOUR POST. Do you think there is a chance your temperature measuring equipment might be the case as well?

Talk to you soon,
Niko
I disagree. I have typically seen blocks that are higher in restriction has less sensitivity to flow rate changes and generally perform better at low flow rates. The more micro pin/fin whatever the smaller the net total cross section which will net higher velocity. Of coarse it is a balancing act with loss in overall net flow rate loss due to the restriction loss.

Take a look at the DT5noz in Strens awesome CPU block work. Vey much an extremely low restriction block with it's parallel nozzle design and also the most gained with increased pumping power.



That has been fairly typical of restriction vs flow sensitivity. Not always but generally what I have seen.

As always I would encourage manufactures to share their own. The more data and the more test benches/conditions the better.

Thanks for all your hard work Stren!

IMHO it seems GPU performance is so darn close here that perhaps VRM cooling is the more important performance differentiator. I know nothing about the card, but I have heard some others GPUs being more sensitive to VRM cooling