Author: Robert Hyatt
Date: 10:14:38 03/20/03
Go up one level in this thread
On March 20, 2003 at 12:11:11, Matt Taylor wrote: >On March 20, 2003 at 10:45:33, Robert Hyatt wrote: > >>On March 20, 2003 at 06:58:18, Frederic Louguet wrote: >> >>>I have a Dual Xeon 2.8 Ghz here (Dell WS450) with 533 Mhz bus, chipset E7505, >>>1 GB ram (2 x 512 PC2100 dual-channel non ECC non Registered), Windows XP Pro >>> >>>ScienceMark 2.0 beta indicates a maximum memory latency of 88.86 ns and a >>>2865 MB/s memory bandwith. >>>I don't run Linux and I don't have LMBench but maybe the ScienceMark results are >>>similar. >> >> >>What about LM Bench? >> >>My dual 2.4's, 2.8's have the E7500 chipset and are reporting 150ns (fastest is >>145) >>with 400mhz FSB and registered ECC RAM (DDR). The 3.06's here have the same >>chipset as yours, with the same 533mhz FSB, but latency is _still_ at 145ns >>roughly. >> >>Perhaps it is the registered / ECC ram that is slowing things down, although I >>would not >>use non-ECC memory on any critical machine. > >Mission-critical, you mean, and Crafty isn't mission-critical... Nope, but crafty isn't the only thing I run. Which explains why it is not on ICC all the time, or is sometimes on using different hardware. > >I've got ECC ram, and I've never experienced a failure in all of the last 9 >months that I've had it. (Failures generate machine check exceptions which get >logged for me, and the only machine checks I have logged were generated by >internal ECC checks on the registers in my Athlon.) My cluster has ECC ram. I have had two failures in the past two years. On Non-ECC machines, we have had multiple failures that were very hard to detect, because a program just crashes but runs fine the next time. Until you stress-test with a memory diagnostic that may (or may not) uncover the problem. > >Non-ECC is faster. I believe it's the registered part that makes it so slow. I >-think- you can buy ECC unregistered, but most companies won't make it because >most people want both at the same time. This is what Micron said, anyway. I'm >pretty sure I've seen ECC unregistered, but it's not terribly popular. There are >usually restrictions on unregistered ram. I have 4 DIMM sockets and can only use >2 unless I use registered ram. Most other DDR boards I've looked at have the >same restriction, from the Abit KG7 to the latest & greatest. > >-Matt I might investigate this just for fun. I _believe_ my dual has 4 x 256 DIMMS, but I don't remember whether it has 8 or 16 slots total (I believe 8 but I'm not going to open it up at the moment.)
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