nForce4 SLI Roundup: Painful and Rewarding

The New Motherboard Test Suite

One of the ongoing concerns at AnandTech has been the tight clustering of performance results in our recent motherboard tests. In general, it is rare to see really wide variations in stock performance with motherboards these days. This has been made even clearer by the AMD Athlon 64 CPU, which has the memory controller on the CPU itself, removing another variable from the chipset equation. This is not bad news for buyers, since more consistent performance at stock speeds makes choosing a motherboard an easier task. Readers have pointed out that we need to do more tests, which would really differentiate boards, and we have been working on updates to our tests.

First and foremost, we have been including overclocking tests and memory stress testing for some time - simply because motherboards can vary a great deal in these capabilities. This tells you which motherboards overclock well and which ones are poor, and even if you don't ever plan to overclock, the ability of a motherboard to run at much higher than stock speeds tells you something about the quality of components used in a motherboard. Good overclockers generally use better components and regulate power on the board better, so the good overclocking boards often make sense to buy even if you will never overclock. You can reasonably expect better stability and a longer service life.

Features are increasingly important in motherboards these days as well. With USB, Firewire, IDE, SATA controllers, RAID, LAN, and audio commonly found on top-line motherboards, you are buying much more than sockets for a processor and memory. There are potentially great variations in performance of these features, which could be very important for certain uses of the board. AnandTech has done a good job of detailing these features in past motherboard reviews, but we confess that we have not done very well in actually testing and comparing performance of these features. Our new motherboard tests are designed to correct that.

Starting with this roundup, we are adding iPeak storage tests first used by Anand in his storage reviews. iPeak will be used to establish baseline performance for nForce4 on-chip IDE and SATA performance; iPeak will also be used to test the throughput of the various additional SATA controllers on these SLI motherboards. USB 2.0 and Firewire 400/800 throughput will be measured with a new test developed for motherboard testing. Basically, we create a RAM disk in Windows XP, write a standard test file to the RAM disk, and then copy the file from the RAM disk to a USB 2.0, Firewire 400 or Firewire 800 connected hard drive. We record the time to copy from RAM disk to the connected drive with a timer program developed by our IT Manager.

Ethernet testing uses the Windows 2000 DDK to connect two computers with a CAT 6 crossover cable. We then use a standard host computer as the server and measure the transmission rate and CPU overhead at the client side, which is our test motherboard. We have talked about the advantages of PCIe over PCI gigabit Ethernet in the past, and in this roundup, you will be able to see the actual difference in the performance of Gigabyte LAN over these two busses.

Audio is an area that is still under development and we will be adding tests of audio quality, as well as do subjective listening in future testing. For this roundup, we have included results from the industry standard RightMark benchmark suite for CPU utilization or overhead. There is only room for so much in a roundup, but in the future, we will definitely be including additional audio benchmarks to our motherboard tests.

Last, we have added some new benchmarks, like the popular video synthetic benchmarks from FutureMark - 3DMark 2005 and 3DMark 2003. These tests are particularly useful for testing SLI, since current nVidia drivers support SLI mode in both benchmarks. We are continuing Winstones 2004 for Business and Multimedia, PCMark04, and AutoGK for media encoding. Games are now more heavily weighted toward the most current games with Half Life 2, Far Cry, Doom 3, and Unreal Tournament 2004. Aquamark 3, which is better known as a benchmark than the game on which it is based, is also continued. Return to Castle Wolfenstein-Enemy Territory and Quake 3 have been retained primarily because of their sensitivity to memory performance. It is also a useful reference to include Open GL-based games with so many new game offerings based on Direct X or sporting DX9 front ends.

We are still experimenting with methods of presenting this new data to you, so please let us know if you have suggestions for the future.

Changes in Memory tRAS Recommendations

In past reviews, memory bandwidth tests established that a tRAS of 10 was optimal for the nForce3 chipset and a tRAS setting of 11 or 12 was generally best for nForce2. In the first memory stress test of a production nForce4 board, tRAS timings were first tested with memtest86, a free diagnostic program with its own boot OS that will boot from either a floppy disk or optical disk. Bandwidth of OCZ PC3200 Platinum Rev. 2, based on Samsung TCCD chips, was measured from tRas 5 to tRAS 11 to determine the best setting.

Memtest86 Bandwidth DFI nForce4 with Athlon 64 4000+
5 tRAS	2191
6 tRAS	2242
7 tRAS	2242
8 tRAS	2242
9 tRAS	2141
10 tRAS	2141
11 tRAS	2092

The best bandwidth was achieved with this combination of nForce4/4000+/TCCD in the 6 to 8 range, so a mid-value tRAS of 7 was chosen for all tests. It appears that optimal tRAS timings may also be memory dependent on the nForce4, so we recommend a quick series of memtest86 to establish the optimum tRAS timings for other memories.