Why the delay, and what’s this with minimum FPS?
We are sure many of you reading will be aware that the 3870 X2 was originally due to be launched on the 23rd January but at what seemed like the last moment the launch was delayed until today, the 28th January. The reason for this has not been particularly clear but the public stance has been that ATI were working on an updated driver, which is true.
The reason for this new driver, and subsequent delay is that when we first received the 3870 X2 and press driver we found numerous performance problems, image quality issues and game crashes when testing. These were reported to ATI and to their credit they worked tirelessly with us to fix all of the issues, which were reproducible. ATI supplied us with beta drivers to test until the final driver (the one in fact used by us today) was ready for use and throughout the last week or so they have shown a great commitment to improving the situation, and as a result the end user experience. We really do need to credit them considerably for their efforts in accepting the issues and getting them quickly resolved.
Driver bugs ranged from minor flickering in Oblivion when first loading a game to Gears of War crashing when configured to use maximum settings. However with the card now performing well and all of the major titles running stable and looking great the end result is a win for everyone involved.
There is still however one outstanding issue with the 3870 X2 which cannot be put to the side. In many tests within this article you will notice that the minimum frames per second figure seems out of line with the rest of the results, ATI had the following comment on this issue:
“In most circumstances we would expect the minimum frame rate found on the ATI Radeon HD 3870X2 to be equal to, or better than an ATI Radeon HD 3870. However, there are conceivable circumstances in which the minimum frame rates of the ATI Radeon HD 3870X2 could be lower. The most obvious case where the ATI Radeon HD 3870X2 could have a lower instantaneous frame rate would be if an application uploaded new information (such as textures or vertex data) to the graphics accelerator during rendering. In this situation the ATI Radeon HD 3870X2 driver has to duplicate the uploaded data, copying the data to each of the GPU frame buffers, which naturally takes more time than uploading a single set of data for a single GPU graphics accelerator.
These circumstances should be rare in practice - as a rule applications try to avoid uploading data during rendering as much as possible as such uploads are known to cause inconsistent frame rates.
An important thing to remember is that if a slow frame is caused by data being uploaded, then the effect will be seen across all graphics accelerators (graphics accelerators with multiple cores will just be affected to a greater degree). The visual result would be a small stutter, probably for a single frame, and if this stutter is noticeable on a ATI Radeon HD 3870X2 it is likely to be noticeable on a single GPU graphics accelerator as well.
In most situations low frame rates are caused by a heavy rendering workload, resulting in low frame rates that are generally seen for an extended period of time. Under these circumstances an ATI Radeon HD 3870X2 will shine, delivering a significantly higher frame rate than a comparable single GPU graphics accelerator thanks to its superior rendering power.”
This seems a fair and honest explanation from ATI, however we do feel that it is worth pointing out that even if single GPU cards are affected by the same issue, our testing shows that it is never to as dramatic an extent as the X2. As a result, when we compare this product to a single core card this has to go down as a failing.