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Memory Nooob, aarrggghh! Using CPU-Z to set timings !!!

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September 14, 2006 5:00:22 PM

I pulled this screenshot to use as my example:
http://www.thg.ru/mainboard/ddr2_memory_2006_rating/ima...

For example, if this RAM was bought with stock timings of DDR2 200Mhz 3-3-3-9, and I wanted to OVERCLOCK IT to 333Mhz, would the required timings be 5-5-5-15, which are derived from the 3rd column in CPU-Z???

I'm trying to get my memory to run 667Mhz with 4-4-4-15 (sold to me with stock on 4-4-4-15 and CAS 4, DDR2 800Mhz).

BOTTOM LINE: Do I need to set my timings to match those specified in CPU-Z, or is this something else and I missed the point. Do I just use the timings at stock?

THAAAANKS!
September 14, 2006 5:43:53 PM

The timings on the SPD are what the stick reports for timing requirements of the memory. In other words, the memory, itself, will not be technically overclocked running these timings, as it would be the designed speed provided by the SPD.

Will this give you improved performance or not is highly variable - depends on your FSB, CPU type (Intel Netburst CPUs benefit from faster ram, while AMDs typically do not show as much of an improvement.) Ideally, you want your FSB to be the same as your memory clock rate. Beyond that, once you move from these SPD timings to faster ones, THEN you will be overclocking... otherwise you are simply running it at spec.

CAS latency seems to be the biggest modifier for performance - lower CAS = better performance, for the most part. I suggest you read the many memory timing articles on the web before seeing what you want to push these to. Overclocking for the sake of running better numbers doesn't always yield an improvement. Often, from what I have seen, lower CAS timings actually provide more improvement than raising the clockrate above FSB levels... but that was a while ago, I'll admit.
September 14, 2006 7:30:23 PM

There are 4 classes of memory speed/timing specs that often get confused with each other. From slowest to fastest they are:

1) SPD settings. Each DIMM has a small EEPROM that the DIMM manufacturer programs with one or more sets of timing info. These "SPD" values are read by the motherboard BIOS on bootup and used for "auto" memory speed/timing setting. Each SPD set of values assumes standard memory voltage (1.8V for DDR2) and lists a memory bus speed (e.g. 333MHz for DDR2-667 speed) along with timings for that speed (e.g. 5.0,5,5,15).
The DIMM is guaranteed to work at these SPD settings, but they are usually chosen to be somewhat conservative, to minimize MB incompatibility problems. Different DIMM manufacturers seem to have slightly different policies on SPD settings. For example, Kingston is known for compatibility (perhaps at some cost in speed) while OCZ seems to emphasize performance (perhaps at some cost in compatibility).

*Important Note:* Any "SPD" settings shown by a software tool (like CPUZ) *have no relation to the actual current speed that your memory is running at* - they are just reading out the values programmed into the SPD EEPROM. You need to look at a different part of your software tool to find the actual memory speed and timings in current use (IIRC, the "Memory" tab for CPUZ or the "Chipset" detail for PC Wizard 2006).

Bottom line: SPD settings are just average or slow speed settings chosen for maximum compatibility with motherboards.

2) Premium-line DIMMs can often run at faster settings than those in their SPDs, even under standard voltage. However, you will need to enter the memory bus speed and timings by hand, using the BIOS, overriding the "auto" setting. Different motherboards have different procedures for this. One key point to remember is that any memory can be set to run on a slower memory bus or with slower timings (bigger latency values) without any problems -- it's running faster that may cause problems.
***Important Warning***: When running memory faster than the SPD settings, ALWAYS use a good memory testing program like memtest86+ and a CPU/memory stress tester like PRIME95 to verify that your system is operating without errors. Otherwise, small errors and corruptions may accumulate unnoticed and eventually ruin your data and/or require a complete reinstall of the OS and programs.

Bottom line: You should be able to run your DIMM at the advertised speed and timings w/o changing the voltage, *as long as the DIMM is rated at standard voltage (1.8V for DDR2),* but you may have to enter the speed and timing settings manually using the BIOS.

3) Manufacturer-sanctioned overclocking. DDR2 memory is currently at the "bleeding edge" of memory development. Although a number of (official and unofficial) standards have been worked out, production chips and DIMMs don't always meet those standards. That doesn't mean the chips or DIMMs are without value, especially given the shortage of higher-speed parts. For example, it's very difficult to find 1GB DIMMs that will run at DDR2-800 at the standard 1.8V. However, manufacturers can now produce plenty of DIMMs that will run at DDR2-800 at a slightly higher voltage, say 2.0V. (Remember, 6 months ago, it was hard to find DIMMs that would run at DDR2-800 under *any* voltage -- this is life on the bleeding edge.)
Thus, they may sell the DIMMs as "DDR2-800" memory, and note in a footnote, or on a spec sheet, that they are only guaranteed to run at DDR2-800 at 2.0V. However, since it may not run at DDR2-800 at 1.8V, they program a slower speed as the max speed in the SPD, so the system will at least boot successfully. This is a major reason why people note that their "DDR2-800" RAM is running at a slower speed on "auto" settings.
When shopping for RAM, for a given memory bus speed (DDR-x or DDR2-x), the closer the spec voltage to the standard voltage (1.8V for DDR2), the better quality the RAM.
*Important note:* In order to be able to run at the manufacturer's spec speed, you need to get ALL the speed specs, including the *DIMM voltage,* from the manufacturer's packaging, web site, or tech support. Then, in your motherboard BIOS, FIRST set the DIMM/memory voltage to the manufacturer's value. Second, set the memory bus speed. Finally, set the timing values.
***Important Warning***: Too high a voltage can permanently damage RAM. Such damage can be identified as overvoltage damage by the DIMM manufacturer. Different manufacturers have different voltage limits on their RAM guarantees, so BE VERY CAREFUL NOT TO EXCEED THE MAX VOLTAGE if the warranty is important to you. IIRC, Corsair's XMS2 max voltage is 2.1V. OCZ guarantees much of its high-end memory to 2.2V. YMMV.
In practice, what this means is that, for example, you shouldn't mix a Corsair module rated at 1.9V in the same system with a Ballistix module rated at 2.2V, as running at the Ballistix spec voltage of 2.2V will void your Corsair warranty.
Recently, Corsair and nVidia have introduced a standard for automatic manufacturer-sanctioned overclocking that they call "EPP". This standard uses additional info stored in previously-unused areas of the SPD memory to provide compatible motherboards with more detailed, higher-performance RAM OC profiles, including memory voltage increases.

Bottom line: Unless your RAM and MB both support EPP, you will have to enter memory voltage, speed, and timings manually in your BIOS to match "factory OC" specs of your module. As long as you do not exceed the factory-specified voltage, the manufacturer will support OCing a module under warranty. However, if you mix different modules in the same system, make sure the necessary voltage for one module does not exceed the limit (and thus void the warranty) for a different one.

4) "Real" overclocking. Finally, in secret workshops running outside any manufacturer limits, this is the real thing! Many DIMMs modules can actually run reliably at faster speeds and/or timings than in their spec. In general, the higher-end product lines are built using better DIMM PCBs and higher-spec RAM chips, and so have more OC potential. "Value" lines are not designed with OC in mind and typically have poor OC potential. However, for mature RAM technologies (like DDR now), sometimes ALL of the chips are high-spec, and thus even "value" DIMMs may be significantly OCable.
There are plenty of guides out there on how to OC, but there's one aspect people often forget: this techonology changes QUICKLY! Especially on the bleeding edge, just because a review OCed a DIMM by 50% doesn't mean you can do the same, even if you get the same part number. Manufacturers continuously make changes to the components, chips, and SPD programming that make up a DIMM, not to mention the chip-to-chip variations as fab conditions are tweaked, etc. RAM reviews even a few months old are best treated as historical documents, not as guides to today's buying decisions.
***Warning***: As pointed out in section (3) above, higher-than-standard memory voltages can and will damage the memory and/or shorten its life. Any OCing done by exceeding the manufacturer's limits on your DIMM will void its warranty, so be prepared to pay out of pocket for any failures caused by your OCing.
Related resources
September 14, 2006 10:02:35 PM

Hey Mondoman,

WOW MAN! That was a mouthful, but ever so informative. I really apprecaite you pulling that together. Really helped me out a lot and makes a lot more sense. I figured out what was going on yesterday. My FSB remained at 267, and my RAM was running at 400 Mhz (remember I set it to DDR2 800 with 4-4-4-15, CAS 4). The ratio is wrong (not 1:1), and this is the only think I can think of that created performance issues. Another addict pointed that out to me on my other post.

I'll clock the RAM down to DDR2 667mhz, and up the FSB to 333 Mhz. That should give me the 1:1 ratio, while that the same time allowing me to keep my 4-4-4-15 timings. YAY! In theory this sounds good. Hope it works out tonight. THANKS AGAIN!
September 15, 2006 3:09:42 AM

This is some great info for understading ram speeds/timings. It ought to be a STICKY.
September 15, 2006 4:35:06 AM

Thanks for the kind words. I posted it so we could link back to it when people have these common timing questions, since the companies aren't doing much to clarify it with their marketing.
September 15, 2006 12:56:29 PM

Damn... I hope that was a cut-paste job, Mondo! That's some MONDO text there.

Couldn't have said it better myself. I was just being a bit lazy, I guess.
September 15, 2006 1:18:39 PM

I ran memtest last night for an hour, and its STABLE at 4-4-4-15, CAS 4 at 2.0V, DDR2 800Mhz. Woohooooooo! Not sure what the heck happened when it kept crashing.

I think I'd rather like to up my FSB to try and get the 1:1 ratio. ie. 400 Mhz and 3.6 Ghz CPU clock. Do you think I can get this on stock cooling, or is that too dangerous? Do I need to get a scythe etc?
August 6, 2007 5:03:14 AM

What temp are you running? And are you air conditioned, or far north?
August 6, 2007 3:30:56 PM

When overclocking memory try to keep the voltage the same as its standard, then simply tighten timings or increase frequency until it just, doesnt work lol.
August 6, 2007 8:25:10 PM

Sengoku said:
What temp are you running? And are you air conditioned, or far north?

Since you're replying to a post from almost a year ago, my guess is you won't get a reply... ;) 
June 8, 2008 5:18:16 PM


That was a very useful post on memory speeds!

You say that DDR2 800 memory with V closer to 1.8 (to reach 800) is better quality memory..

I want to OC my Q6600 to have 333 FSB. Running at 1:1, that translates to 667 for the DDR2 memory. Does that mean I don't need to raise the voltage on DDR2 800 memory beyond 1.8 (or in general, the voltage is less of an issue)?

Can I get cheaper RAM running at 4-4-4-12 ( such as this CORSAIR http://www.newegg.com/Product/Product.aspx?Item=N82E168... ) instead of apparently better quality and more expensive 5-5-5-15 (such as this G.SKILL http://www.newegg.com/Product/Product.aspx?Item=N82E168...)?

The former says 2.1V in the Voltage Specif. while the latter says 1.8 - 2.0 V. But does this matter less to me since these V are for reaching 800 while I only need 667?

Thanks a lot!
May 15, 2009 3:06:34 PM

Mondoman said:
There are 4 classes of memory speed/timing specs that often get confused with each other. From slowest to fastest they are:

1) SPD settings. Each DIMM has a small EEPROM that the DIMM manufacturer programs with one or more sets of timing info. These "SPD" values are read by the motherboard BIOS on bootup and used for "auto" memory speed/timing setting. Each SPD set of values assumes standard memory voltage (1.8V for DDR2) and lists a memory bus speed (e.g. 333MHz for DDR2-667 speed) along with timings for that speed (e.g. 5.0,5,5,15).
The DIMM is guaranteed to work at these SPD settings, but they are usually chosen to be somewhat conservative, to minimize MB incompatibility problems. Different DIMM manufacturers seem to have slightly different policies on SPD settings. For example, Kingston is known for compatibility (perhaps at some cost in speed) while OCZ seems to emphasize performance (perhaps at some cost in compatibility).

*Important Note:* Any "SPD" settings shown by a software tool (like CPUZ) *have no relation to the actual current speed that your memory is running at* - they are just reading out the values programmed into the SPD EEPROM. You need to look at a different part of your software tool to find the actual memory speed and timings in current use (IIRC, the "Memory" tab for CPUZ or the "Chipset" detail for PC Wizard 2006).

Bottom line: SPD settings are just average or slow speed settings chosen for maximum compatibility with motherboards.

2) Premium-line DIMMs can often run at faster settings than those in their SPDs, even under standard voltage. However, you will need to enter the memory bus speed and timings by hand, using the BIOS, overriding the "auto" setting. Different motherboards have different procedures for this. One key point to remember is that any memory can be set to run on a slower memory bus or with slower timings (bigger latency values) without any problems -- it's running faster that may cause problems.
***Important Warning***: When running memory faster than the SPD settings, ALWAYS use a good memory testing program like memtest86+ and a CPU/memory stress tester like PRIME95 to verify that your system is operating without errors. Otherwise, small errors and corruptions may accumulate unnoticed and eventually ruin your data and/or require a complete reinstall of the OS and programs.

Bottom line: You should be able to run your DIMM at the advertised speed and timings w/o changing the voltage, *as long as the DIMM is rated at standard voltage (1.8V for DDR2),* but you may have to enter the speed and timing settings manually using the BIOS.

3) Manufacturer-sanctioned overclocking. DDR2 memory is currently at the "bleeding edge" of memory development. Although a number of (official and unofficial) standards have been worked out, production chips and DIMMs don't always meet those standards. That doesn't mean the chips or DIMMs are without value, especially given the shortage of higher-speed parts. For example, it's very difficult to find 1GB DIMMs that will run at DDR2-800 at the standard 1.8V. However, manufacturers can now produce plenty of DIMMs that will run at DDR2-800 at a slightly higher voltage, say 2.0V. (Remember, 6 months ago, it was hard to find DIMMs that would run at DDR2-800 under *any* voltage -- this is life on the bleeding edge.)
Thus, they may sell the DIMMs as "DDR2-800" memory, and note in a footnote, or on a spec sheet, that they are only guaranteed to run at DDR2-800 at 2.0V. However, since it may not run at DDR2-800 at 1.8V, they program a slower speed as the max speed in the SPD, so the system will at least boot successfully. This is a major reason why people note that their "DDR2-800" RAM is running at a slower speed on "auto" settings.
When shopping for RAM, for a given memory bus speed (DDR-x or DDR2-x), the closer the spec voltage to the standard voltage (1.8V for DDR2), the better quality the RAM.
*Important note:* In order to be able to run at the manufacturer's spec speed, you need to get ALL the speed specs, including the *DIMM voltage,* from the manufacturer's packaging, web site, or tech support. Then, in your motherboard BIOS, FIRST set the DIMM/memory voltage to the manufacturer's value. Second, set the memory bus speed. Finally, set the timing values.
***Important Warning***: Too high a voltage can permanently damage RAM. Such damage can be identified as overvoltage damage by the DIMM manufacturer. Different manufacturers have different voltage limits on their RAM guarantees, so BE VERY CAREFUL NOT TO EXCEED THE MAX VOLTAGE if the warranty is important to you. IIRC, Corsair's XMS2 max voltage is 2.1V. OCZ guarantees much of its high-end memory to 2.2V. YMMV.
In practice, what this means is that, for example, you shouldn't mix a Corsair module rated at 1.9V in the same system with a Ballistix module rated at 2.2V, as running at the Ballistix spec voltage of 2.2V will void your Corsair warranty.
Recently, Corsair and nVidia have introduced a standard for automatic manufacturer-sanctioned overclocking that they call "EPP". This standard uses additional info stored in previously-unused areas of the SPD memory to provide compatible motherboards with more detailed, higher-performance RAM OC profiles, including memory voltage increases.

Bottom line: Unless your RAM and MB both support EPP, you will have to enter memory voltage, speed, and timings manually in your BIOS to match "factory OC" specs of your module. As long as you do not exceed the factory-specified voltage, the manufacturer will support OCing a module under warranty. However, if you mix different modules in the same system, make sure the necessary voltage for one module does not exceed the limit (and thus void the warranty) for a different one.

4) "Real" overclocking. Finally, in secret workshops running outside any manufacturer limits, this is the real thing! Many DIMMs modules can actually run reliably at faster speeds and/or timings than in their spec. In general, the higher-end product lines are built using better DIMM PCBs and higher-spec RAM chips, and so have more OC potential. "Value" lines are not designed with OC in mind and typically have poor OC potential. However, for mature RAM technologies (like DDR now), sometimes ALL of the chips are high-spec, and thus even "value" DIMMs may be significantly OCable.
There are plenty of guides out there on how to OC, but there's one aspect people often forget: this techonology changes QUICKLY! Especially on the bleeding edge, just because a review OCed a DIMM by 50% doesn't mean you can do the same, even if you get the same part number. Manufacturers continuously make changes to the components, chips, and SPD programming that make up a DIMM, not to mention the chip-to-chip variations as fab conditions are tweaked, etc. RAM reviews even a few months old are best treated as historical documents, not as guides to today's buying decisions.
***Warning***: As pointed out in section (3) above, higher-than-standard memory voltages can and will damage the memory and/or shorten its life. Any OCing done by exceeding the manufacturer's limits on your DIMM will void its warranty, so be prepared to pay out of pocket for any failures caused by your OCing.


By the way here’s my problem help me please

Choosing best memory for this budget gaming build
budget gaming build so cheaper is better but depending on the price to performance ratio if it boost a lot of performance i will spend couple of dollars for that.

SYSTEM USAGE FROM MOST TO LEAST IMPORTANT: Gaming , Surfing the net.

PARTS PREFERENCES: Brand availlable in my country is only kingston, giel and cosair.

OVERCLOCKING: No Maybe SLI OR CROSSFIRE: No

MONITOR RESOLUTION: 1440x900


AMD Athlon 64 X2 7750 Kuma 2.7GHz 2 x 512KB L2 Cache 2MB L3 Cache Socket AM2+ 95W Dual-Core black edition
http://www.newegg.com/Product/Prod [...] 6819103300

GIGABYTE GA-MA78GM-US2H AM2+/AM2 AMD 780G HDMI Micro ATX AMD Motherboard
http://www.newegg.com/Product/Prod [...] 6813128379

SAPPHIRE 100277L Radeon HD 4770 512MB 128-bit GDDR5 PCI Express 2.0 x16 HDCP Ready CrossFire
http://www.newegg.com/Product/Prod [...] 6814102835



First question 4GB (2 x 2GB) or 2GB ( 2 x 1GB )? and pc 667, 800 or 1066?

2GB (2 x 1GB) DDR2 - 667
2GB (2 x 1GB) DDR2 - 800
2GB (2 x 1GB) DDR2 - 1066

4GB (2 x 2GB)
4GB (2 x 2GB)
4GB ( 2 x 2GB)

Second what brand is better?
Kingston
Cosair
Giel


any help would be much appritiated


!