FIRST LOOK: ULi M1695 PCIe/AGP Socket 939 for Athlon 64

tRAS and Memory Stress Testing

Memory tRAS Recommendations

In past reviews, memory bandwidth tests established that a tRAS setting of 11 or 12 was generally best for nForce2, a tRAS of 10 was optimal for the nForce3 chipset, and a tRAS of 7 was the best choice for the nForce4 chipset. Since this is our first review of a ULi chipset, 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 13 to determine the best tRAS setting for the ULi chipset.

Memtest86 Bandwidth ULi M1695 with Athlon 64 4000+
5 tRAS	1874
6 tRAS	1913
7 tRAS	1953
8 tRAS	1953
9 tRAS	1994
10 tRAS	1994
11 tRAS	1994
12 tRAS	1874
13 tRAS	1974

The best bandwidth was achieved with this combination of ULi M1695/4000+/TCCD in the 9 to 11 range, so a mid-value tRAS of 10 was chosen for all tests. It appears that optimal tRAS timings may also be memory dependent, so we recommend a quick series of memtest86 to establish the optimum tRAS timings for other memories on the ULi chipset.

Memory Stress Test

Our memory stress test measures the ability of the ULi to operate at its officially supported memory frequency (400MHz DDR), at the lowest memory timings that OCZ PC3200 Platinum Rev. 2 modules will support. All DIMMs used for stress testing were 512MB double-sided (or double-bank) memory. To make sure that memory performed properly in Dual-Channel mode, memory was only tested using either one dual-channel (2 DIMMs) or 2 dual-channels (4 DIMMs).

Stable DDR400 Timings - One Dual-Channel (2/4 DIMMs populated)
Clock Speed:	200MHz
CAS Latency:	2.0
RAS to CAS Delay:	2T
RAS Precharge:	10T
Precharge Delay:	2T
Command Rate:	1T

Using two DIMMs in Dual-Channel 128-bit mode, the memory performed in all benchmarks at the fastest 2-2-2-10 timings at default voltage, which was the only memory voltage available.

Stable DDR400 Timings - 4 DIMMs (4/4 DIMMs populated)
Clock Speed:	200MHz
CAS Latency:	2.0
RAS to CAS Delay:	2T
RAS Precharge:	10T
Precharge Delay:	2T
Command Rate:	2T

Tests with all four DIMM slots populated on the ULi M1695 required a 2T Command Rate with 4 DIMMs in two dual channels. This is the pattern seen on other top-performing Socket 939 boards. However, the ULi had no problem running at a 200 CPU speed setting with 4 double-sided DIMMs. This performance is certainly competitive with the best that we have seen on nForce4 motherboards for Socket 939.