A Memory Question

Gigabyte / G41m-es2h
November 12, 2010 at 22:55:51
Specs: Windows 7, 3.52 GHz / 4094 MB
This question is not for the computer I am currently using to post. The actual specs are:
GA-EP43-UD3L, Core 2 Duo E8200, OC to 3.2GHz (400x8), Crucial Ballistix 4GB (2x2GB) set 800MHz DDR2 listed as 4-4-4-12 2.0V, PNY GTS250 GDDR3 1GB, WD500GB Black.

CPU-Z shows under Memory:
Dram Freq. 400.0 MHz
CAS# Latency (CL) 5.0 Clocks
RAS to CAS# Delay (tRCD) 5 Clocks
RAS# Precharge (tRP) 5 Clocks
Cycle Time (tRAS) 18 Clocks
Row Refresh Cycle Time (tRFC) 52 Clocks
Command Rate (CR) 2T

Under SPD tab it shows 4 columns:
Timings Table JDEC#1 JDEC#2 EPP#1 EPP#2
Frequency 333MHz 400MHz 400MHz 500MHz
CAS# Latency 4.0 5.0 4.0 5.0
RAS# to CAS# 5 5 4 5
RAS# Precharge 5 5 4 5
tRAS 15 18 12 15
tRC 20 23 24 30
Command Rate 2T 2T
Voltage 1.8V 1.8V 2.000V 2.000V

My question is, are these optional memory timings? It is running at 1.8 Volts at what appears to be the JEDEC#2 settings above, and I suspect that the JEDEC#1 above might be better settings if I was running the memory at 333Mhz (667DDR2). Am I right on this, and what does the EPP#1 & EPP#2 columns? Are they also also timings that these can run at? Is EPP#1 a 'tighter' timing that might be better? Is EPP#2 mean that I could run these settings and up to 1000DDR2 if I want to try running beyond the 400MHz base speed? AND is there a chance that my board will support over 1600FSB with slightly more voltage? ((I guess that is a lot more than a singular question!!)) [Everything is running great at these settings with temps 40C-50C on stock heat sink, this is more for my education and for possible future experimentation] As always, Thank You in advance.
Edit: too bad the columns did not stay on that last chart.

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November 13, 2010 at 07:13:11
SPD (Serial Presence Detect) is the settings that are pre-programmed into the EEPROM on the RAM module. The motherboard/BIOS reads the SPD data & auto-configures the RAM to these settings UNLESS the user overrides them & configures the settings manually.

The JEDEC (Joint Electron Device Engineering Council) standard for DDR2 memory states that ALL DDR2 SDRAM should run at 1.8v.

EPP (Enhanced Performance Profiles) is additional info programmed into the EEPROM that provides high performance settings. It was develeoped by nVidia & Corsair, then adopted by several other RAM manufacturers. As far as I know, the EPP BIOS setting is only available on nVidia based motherboards. EPP is NOT supported by JEDEC.

Intel developed it's own high performance settings called XMP (eXtreme Memory Profiles) which works similar to the above.

You already have your ratio correctly configured at 1:1, don't change it! If it were my system, I would disable the SPD option in the BIOS & configure the RAM timings manually. Try for 4-4-4-12. Increasing the voltage does NOT increase speed, but it *may* be necessary to stabilize the RAM at these tighter timings. Bumping it up to 2.0v probably isn't necessary - you may find that 1.85v or 1.9v is all you need. Keep the RAM voltage as close to 1.8v as possible. Remember, higher voltage = higher temps.

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November 13, 2010 at 16:29:28
Thank you for the education and the advise. I was NOT going to OC the ram unless I could get the board beyond 1600FBS, then the 2.0 memory multiplier would keep it at a 1:1 Ratio. For now, I will probably WILL try the tighter timings (but loosen them up again if I decide to try over 400MHz base timing) though, it should pick up the memory performance at least a little. I wasn't looking for another automatic setting, but tested options to begin setting manually and apparently these should help. Thank you again. Anything anyone would like to add would be appreciated.

You have to be a little bit crazy to keep you from going insane.
If all else fails, read instructions.

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