Clash of the Titans VGA 2014 – ASUS Geforce GTX 780 Ti DirectCU II vs ASUS Radeon R9 290X DirectCU II
ASUS Geforce GTX 780 Ti DirectCU II vs ASUS Radeon R9 290X DirectCU II
A few months ago I made a promise on the forums that I would write an article on overclocking in which the GeForce GTX 780 Ti would face the Radeon R9 290X in a true battle of the VGA titans. At that time, reference models were the only ones available and neither of them being particularly well suited for serious overclocking or endurance testing, mostly due to their far from stelar VRMs. Given this, the results would have been mediocre at best, and surely the testing would have ended with a couple of “funerals.”
I really love a GPU with a huge die area because this translates into many transistors and immense computing power, very well suited for benchmarking. A big GPU demands respect and comes with a certain wow factor when you first lay your eyes on the silicon die, as those who have seen a G200 without the IHS know very well. The G200 still has the biggest die area of any current and past GPUs, being one of the few members of the 400mm+ club, which you can see below. AMD joined this club last year with their first GPU that fits the size criteria, I’m referring to the Hawaii core with its 438mm die.
So we have the most powerful GPUs ever produced by NVIDIA and AMD, and both will be subjected to extended stress testing under tough conditions just so we can properly evaluate the strengths of the DirectCU II designs. We will test their overclocking potential on both air and water and we’ll see how both cards scale with voltage and temperature. In a sense we are lucky because both GPUs have the same ASIC quality (72%) as measured by GPU-Z, which is good for our head to head comparative testing, but may not be so good for the final overclocking results (over 80% ASIC quality as measured by GPU-Z is preferred).
Anyway, you can’t really rely on such values when evaluating a GPUs potential, there’s no replacement for actual testing, even so I’m not that pleased with the ASIC values, I wanted to see some big numbers, even if just for “peace of mind” purposes. Speaking of “silicon quality”, the ASIC quality is no guarantee for anything as there are two other very important factors that influence the overclocking potential more than the ASIC does: voltage and temperature scaling. Or if we move to extreme cooling, there are even more influential factors involved, such as coldbug, coldboot and cold scaling .
The graphics cards from ASUS’ DirectCU II series are my favourites when it comes to bench and, before proceeding, I would like to share my latest experience with a VGA card from this series: using an ASUS Geforce GTX 580 DirectCU II I have exceeded 1100MHz GPU clock for 3DMark Vantage, a difficult load for GF110.
The DirectCU II version of the GTX 580 is a work of art, from overall strength to individual component quality and GPU VRM stability, built with no less than 32 MOSFETs (for comparison purposes, I can tell you that the MSI Lightning GTX 580 only has 28).
- ASUS Geforce GTX 580 DirectCU II – 1143MHz Vantage @ watercoling (worth mentioning that the highest frequency on HWBot in Vantage with the GPU on WC is 1100MHz)
Another important fact when talking about quality: look carefully at the corners of the GPU and you will notice that it is fixed with adhesive for added protection in case of PCB bending. Long time ago, on certain video cards a metal frame was fixed around the GPU, one of them being the 8800GTX, a legend that’s still alive.
There are many other details that would not be noticed by an untrained eye, such as the PCB bending due to bad cooler design (see MSI), component placement on the PCB, soldering quality, VRM MOSFET positioning so that it will allow direct contact with the metal heat sink for best heat transfer, and many others …
As a simple example: fitting the GTX 580 DirectCU II with a ZEROtherm HC92 doesn’t generate any bending of the PCB, while on the MSI GTX 570 TFIII PE the same cooler will visibly bend the PCB. It doesn’t really impact performance but it matters to me, as everything has to be perfect in order for me to be completely satisfied. Even if it has a big and ugly cooling system, the GTX 580 DirectCU II is the standard by which all the other video cards will be “judged.”
Unfortunately, just like in the cooling industry these days, the trend here is to reduce quality, a practice that I can not agree with and I will keep pointing out every single flaw or unsatisfactory aspect that I notice. This is not an article for the average user so we cannot get over certain critical aspects for us overclockers and technology freaks.