Lavalys Everest Memory Performance

Website: Lavalys



The raw, optimised read performance of the XFX nForce 790i Ultra SLI is better than the Gigabyte X48T-DQ6, although the Gigabyte keeps up when it comes to write and copy performance. In fact, all the systems (both DDR2 and DDR3), have very similar copy and write speeds, it's just that DDR3 benefits from an improved read performance.

At the time of testing the XFX nForce 790i Ultra SLI board, we used the P03 BIOS and it would not accept CAS latencies lower than 8 – this was a small problem when we were trying to optimise for low latency at 1,600MHz. At this speed, the lowest stable latencies we could achieve were 8-6-6-17-30tRFC-5tWR-1T and in contrast the best timings we could get from the Gigabyte X48T-DQ6 were 7-6-6-18-1T.

We also found our Corsair Dominator 1,800MHz C7 performed better than the Crucial Ballistix 2,000MHz C9. The Crucial even had EPP2.0 which we tried testing, but found it to not only be very unstable at 2,000MHz, but also slower than our optimised timings at 1,600MHz. At a super high 2GHz clock speed, its latencies were an equally high 9-9-9-27-2T which gave us: read: 9565MB/s, write: 8088MB/s, copy: 8029MB/s and a latency of 55.3ns. We've always had good results with EPP on DDR2 platforms, so we're hoping that these are just teething problems and that EPP 2.0 support will evolve with DDR3 development.

On one hand it's quite surprising given the fact the DDR3 is operating at twice the frequency of the DDR2, however it's also running at "double" the latency – when both DDR2 800MHz and DDR3 1,600MHz run in sync with the 1,600MHz FSB QX9770 CPU, it really works that much better. The XFX nForce 780i SLI BIOS is exceptionally good and well-optimised, as is demonstrated by its memory latency results.

The DFI X48-T2R DDR2-based board suffers because the X48 chipset is predominantly designed for DDR3, so partnering it with DDR2 isn't the ideal choice when it comes to performance. In addition, the DFI board was very difficult to really optimise, not just because of its complicated BIOS, but also because it was simply unstable whenever we tried new combinations of settings – we are currently working with DFI to resolve these issues.

SiSoftware Sandra Lite XII.2008.SP1 (13.12)

Website: Sisoftware



Sisoft Sandra tells a slightly different story, as here the Gigabyte X48 board outperforms the XFX nForce 790i Ultra SLI with either CPU—even the XFX nForce 780i SLI comes out very poorly. However the XFX 790i latency is very low - lower than everything else.