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 optimal for the nForce4 chipset. The recently tested ULi 1695 was best at tRAS of 10.

Since this is our first review of a new ATI 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 12 to determine the best setting.
Memtest86 Bandwidth
Sapphire PURE Innovation with Athlon 64 4000+
5 tRAS 2048
6 tRAS 2092
7 tRAS 2141
8 tRAS 2141
9 tRAS 2092
10 tRAS 2048
11 tRAS 2004
12 tRAS 1922

Two things stood out in our tRAS tests. First, the Sapphire ATI exhibits the best bandwidth at a tRAS setting of 7 or 8. We decided to use 7, since it is the same as the best setting for nForce4. Second, the bandwidth numbers on the ATI were a bit higher across the tRAS tests than what we saw with the ULi 1695. This suggests ATI having better optimized memory management - at least at this stage of development.

Memory Stress Test

Our memory stress test measures the ability of the Sapphire ATI 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: 7T
Precharge Delay: 2T
Command Rate: 1T

Using two DIMMs in Dual-Channel 128-bit mode, the memory performed in all benchmarks at the fastest 2-2-2-7 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: 7T
Precharge Delay: 2T
Command Rate: 2T

Tests with all four DIMM slots populated on the Sapphire required a 2T Command Rate with 4 DIMMs in two dual channels. This is the pattern seen on other top-performing Socket 939 boards. The Sapphire AMD had no problem running at a 200 CPU speed setting with 4 double-sided DIMMs. Since the Athlon 64 memory controller is on the processor, there were no real surprises in the memory stress tests. The Sapphire ATI is certainly competitive with the best Socket 939 boards in memory performance.

Overclocking: Sapphire PURE Innovation Test Setup
Comments Locked

52 Comments

View All Comments

  • RobFDB - Saturday, July 30, 2005 - link

    Guess you missed where i said "(with the exception of MSI)". Learn to read mate before you go posting.
  • RobFDB - Friday, July 29, 2005 - link

    ATI and Sapphire should be congratulated for bringing the AC880 to AMD users. We had it good with Soundstorm but since then onboard audio as gone back several steps (with the exception of MSI). Its good that AMD users are being given the option to have quality onboard audio.
  • bob661 - Friday, July 29, 2005 - link

    This what impresses me the most about these boards is this codec support. I still won't buy an ATI chipset until the third or fourth version comes out (you guys can test it for me) but impressive features and performance nonetheless.
  • jab98 - Friday, July 29, 2005 - link

    *codec
  • erwos - Friday, July 29, 2005 - link

    "[AMD] Enthusiast" is written with a capital E in the article, and it should not be, since it's not a proper noun. Please fix this error, because it looks grossly unprofessional to anyone with a reasonable command of the written word.
  • RobFDB - Friday, July 29, 2005 - link

    Really though, get over it. It doesnt matter in the slightest if we're being honest here. Anyway back to more important matters.

    I'm really happy that ATI have managed to bring a top performing board aimed at enthusiasts to market. I was also extremely impressed to see Sapphire implement 4v for the RAM. One issue that i'd like to see investigated is wether the cold boot issue that affects DFI NF4 boards using OCZ VX mem @ high voltages affects the Sapphire board too. Aside from that this is a very impressive showing from ATI. One last thing. I have a x850XT PE and i'm not sure if that can be used as a slave card when ATI bring out the R520. If so that would make a very attractive upgrade.
  • rjm55 - Friday, July 29, 2005 - link

    The X850XT PE works fine as a slave with the X850 Master Card. In demos at Computex, ATI was showing an X850 Master with an X850XT PE slave.
  • Jojo7 - Friday, July 29, 2005 - link

    This isn't exactly true. Ati distributed a special driver that SIMULATED crossfire. The actual cards were really just 2 identical x850xtpe's. Though, one probably had an altered bios to simulate a master card.

    Read it for yourself: http://anandtech.com/weblog/default.aspx?bid=231">http://anandtech.com/weblog/default.aspx?bid=231
  • dlamblin - Friday, July 29, 2005 - link

    Did I miss the mention in the article? Is this an ATX or an mATX board. I'm guessing the former, but it wouldn't be out of place to list the fact along side the rest.
  • erwos - Friday, July 29, 2005 - link

    It's ATX. If it has more than four slots, it's too big to fit the mATX standard.

Log in

Don't have an account? Sign up now