Understanding advanced RAM settings

[Kivin]

Hi.
I started tweaking my computer's settings recently. There's a few things in particular that I'm unsure of:

What is the MCH Latch and why would I use it? My motherboard gives me about four or five MHZ ratings from 200 up to 400 which appears to affect my RAM speed, but I've not really been able to get a clear answer on whether it should just be left to [Auto] or configured.

Secondly, my RAM is rated at "5-5-5 @ 2.1"
My BIOS defaults are 5-7-7-24 @ 1.8; However I've been unable to get the system to POST on any of the following:

5-5-5-15 @ 2.1
5-7-7-24 @ 2.1
7-7-7-24 @ 2.1

Which leads me to believe my RAM just doesn't like the voltage I'm giving it. That makes me wonder if there's maybe something else that I'm not configuring correctly?

edit: My ram is rated at 1150 Mhz on the box and shows rated 1066 Mhz in the BIOS, all the above is with it clocked between 900 and 1000.

[JaY_III]

As for your RAM the default speed is read from the SPD data programed into your RAM.
This is normally not its rated speed but more of a fail safe speed if you will.

Here is a very useful resource for your BIOS and its settings
http://www.techarp.com/show.aspx?fileID=18

Should explain pretty much every setting you have

[Albyno]

your rams fourth timing is 18 to make it 5-5-5-18 stock. i run the same stuff. i can get mine to run np at 5-5-5-15 at 1260+mhz with 2.2 volts. you ram is rated to run at 2.2v so dont worry about going that high.

[Kivin]

Thanks, both. When I get off work, I'll look at that techarp link and see if it gives me the ammunition to get this stupid thing POSTing at 2.1

[18 is # 1]

You might try the OCZ forum:http://www.ocztechnologyforum.com/forum/forumdisplay.php?f=46

[Kivin]

Thanks for the link. I guess I'll have to try the OCZ forum since I'm not really getting the answers I need, here. The techarp link above doesn't explain my BIOS settings at all, or if it does, it renders the explanations impotent due to using different tech jargon than my own BIOS.

I appreciate the help so far, but if someone wants to take a stab at this, all the better. I've got the following settings in my BIOS:

* = selected.

-- DRAM Performance Control --

Performance Enhance:
enum (Standard, *Turbo, Extreme)
"Allows the system to operate at three different performance levels."

Extreme Memory Profile (XMP)
enum (*Disabled, Profile1, Profile2)
"Allows the BIOS to read the SPD data on XMP memory modules to enhance memory performance when enabled."

(G)MCH Frequency Latch
enum (*Auto, 200Mhz, 266Mhz, 333Mhz, 400Mhz)
"Allows you to fix the chipset frequency at system bootup."
This one in particular I'm unsure of. Seems archaic to me. No one appears to know what it does or why I should (or should not) use it. I've toyed around it it a bit to see how it influences my RAM speeds and not really been able to put my finger on it.

System Memory Multiplier (SPD)
choices "2.00A", "3.00A", more...
"Options for adjusting memory multiplier may differ according to the fixed frequency."
This clearly is my FSB to DRAM ratios, though it's presented in a way I've certainly never seen before. In the right-hand information panel in the BIOS, it has a legend:
A = FSB 200
B = FSB 266
C = FSB 333
D = FSB 400
or something close to that. If the Latch is (Auto), it gives me a huge matrix of choices like (2.00x, 2.50x, 3.00x, ...) where "x" is A, B, C, D. If Latch is set to a fixed value, only the "A" choices are available and only the ones 2.00, 3.00, and 4.00

DRAM Timing Selectable
*enabled/disabled

CAS, tRCD, tRP, tRAS - all currently left at defaults 5-7-7-24.

After that are voltage controls for all the above and more.

[18 is # 1]

Performance Enhance:
enum (Standard, *Turbo, Extreme)
"Allows the system to operate at three different performance levels."

Extreme Memory Profile (XMP)
enum (*Disabled, Profile1, Profile2)
"Allows the BIOS to read the SPD data on XMP memory modules to enhance memory performance when enabled."
.

If you have "Enhanced Performance Profile" option on your mobo, the RAM will set itself.

[bing]

Complementing above links & explanations, from the MemSet's author -> HERE (http://www.tweakers.fr/timings.html).










.

[Kivin]

Since this seems to pop up on Google for a lot of things I search, I'll add in my solution to my EP45-DS3L not accepting "Manual" Memory settings:

As it turns out, even with the DRAM settings on "Manual", the "Performance Enhance" setting needs to be adjusted from "Turbo" to "Standard."
As soon as I set that, system started POSTing with correct RAM timings and voltage.

Still wondering if there's any problem with using an MCH Latch faster/slower than my FSB?