In practice
We first looked at the performance of the memory controller tested with the help of ScienceMark 2 for latency speeds, as well as the framerate in Far Cry, and compression of files obtained with WinRAR 3.7. These two « practical » applications were chosen because they can be noticeably affected by the speed of the memory sub-system, however, this isn’t always the case.
Whether it’s with an FSB set at 333 MHz or 444 MHz and with processor frequency of 2666 MHz, the X38 has trouble setting itself apart from the P35. We gain 1 to 3 cycles in memory access and indeed up to 368 MB /s in bandwidth. However, in practice the gains are very limited at 0.4 to 0.9% in WinRAR and at best 1% in Far Cry.
We now move on to PCI-Express speed measured with the help of a GeForce 8800 GTX on each of the card’s two PCI-Express x16 ports in three distinct tests:
- Serious Magic, a test which carries out a download from the graphic card to the system
- SPECViewperf9 UGS Teamcenter, an OpenGL graphic load simulation and very heavy professional use
- 3DMark2006, here we took the score for the two scenes of HDR/SM3.0 in 1680x1050 AA4x
Contrary to what occurs on the P35, the performances offered by these two slots are now comparable. In addition, and despite the fact that the GeForce 8800 isn’t PCI-E 2.0, we saw a notable increase in the speed measured in Serious Magic, even if this does not have an evident impact on practical performances.
Power consumption of the P53E motherboard compared to a P5K3 Deluxe in the same conditions is very comparable.
Finally, what about overclocking ? To take a look at the behavior of the chipset in this area, we used a QX6850 and tried to obtain the highest possible FSB. We remained in Strap 333, because 400 would not have given us better results. By staying with a value of 1.25V for the chipset, we were able to obtain 480 MHz of FSB, then 490 MHz by increasing voltage to 1.45V. The CPU PLL also went from 1.5 to 1.7V. This was the maximum stability we were able to reach and validated in two 30 minute sessions of Prime95. For the P35 on the P5K3 in the same conditions, we obtained 470 MHz without increasing voltage and 480 MHz by increasing the chipset power to 1.55V.
Conclusion
This first look at the X38 chipset isn’t the most conclusive. We know that the P35 is lacking in terms of PCI Express management, something of greater importance for those that want to use multiple graphic cards, however, the limitation to CrossFire and absence of SLI compatibility is still problematic. Also, in terms of performances and overclocking, while there was a slight improvement compared to the P35, it’s more symbolic than anything.
In short, given the current situation, the X38 is a bit disappointing. The P35 Express was already very good and it’s true that it would have been difficult to do significantly better. However, given the absence of major improvements between the two cards, for example, in the bios, it’s going to be difficult justify a large difference in price.
