ddr2 1:1 ratio?

jepherz · Jul 14, 2008, 11:31 PM

i just saw this while shopping for ram:
Newegg.com - OCZ SLI-Ready Edition 2GB (2 x 1GB) 240-Pin DDR2 SDRAM DDR2 1066 (PC2 8500) Dual Channel Kit Desktop Memory - Desktop Memory

under customer review the guy says:
Pros: As in all matters technical in the universe, there exists a mathematical relationship, a formula if you will, that determines the performance of memory as a component of your communication bus. Your Front Side Bus and Volatile Memory frequencies are usually most efficient and stabile when set at a 1:1 ratio, although some older ram and motherboards actually utilize a 5:4 or 3:2 ratio that is usually not sustainable on Double Data Rate 2 Modules. But how is this 1:1 frequency relationship calculated? There exists a ""Native Bus"" frequency factor that is usually some multiple of an original 33MHz and continuing with 66MHz, 100MHz etc. These settings determine both RAM and Mobo frequency ratings and the relationship between the two is controlled by a factor of 2 (double) for Ram and 4 (quad) for the Front Side Bus. As you can see there is an inherent disproportion between ram and the fsb. When you look at your motherboard's FSB ratings you will generally today see 1066MHz, 1333MHz.....Cons: or 1600MHz capabilties, which when divided by 4 will give you the factor for this ""Native Bus"" which will in turn control the frequency setting of your Ram. As an example...if your Mobo FSB is 1333MHz, then the ""Native Bus"" is (1333/4) = 333.25MHz so your most stabile Ram frequency will now be double that (333.25 x 2) = 666.5 or DDR2-667. Following the above explanation then, if you insert DDR2-1066 modules into Mobo with a 1333MHz FSB, the Mobo will probably utilize this Ram at the lower, but more stabile for data throughput, rating of DDR2-667 as displayed in your system Bios...this is by default. You must ALWAYS overclock the Ram to obtain the higher value....but keep in mind that you will probably have to raise the frequency for the FSB as well in order to maintain that 1:1 ratio for system stability. This is where voltages must be raised as OCZ time and again states in an effort to support the new frequencies...it takes increasing electrical energy to support the ratings.......Other Thoughts: you have raised in your bios or 3rd party tool of choice. I have scored 19820 points in 3DMark06 with an E8400 | 780i EVGA | 8800GTS SLI using 4Gb's of this OCZ ram clocked at 939MHz (under 1066MHz) but I had an 1877 (remember 2 x 939) FSB, with the mobo as the limiting factor. That results in a 41% OC on the CPU (1877/4 = 469 fsb so with a Cpu multiplier of 9 (x 469) = 4.22 GHz on a stock 3.0GHz E8400 Intel). And I'm back today to buy more of this Great Ram for a 9950 Phenom build on an MSI K9A2 O/C Mobo...yes its compatible here too. Having said all this...the best advice is that if you are not into overclocking (voids warranties!) then just use the 2 x 4 rule (2x for Ram ~ 4x for FSB) and you will achieve stability and happiness! And.... Oh yeah...you don't look stupid to either the OCZ technical staff...or other 'EggHeads reading your gibberish about how you gotta' dead stick from OCZ...which is really just a random Genetic outcome from my perspective....capish paisano?

i have a 1333 fbs mobo and 1066 ram support...what does that mean for me? if i buy 1066 it will run as 667 default and i need to overclock both my ram and mobo for it to work at that speed? is the 1 stick of 800 i have installed right now running at 667?

Lowfat · Jul 15, 2008, 01:37 AM

If you have a 1333MHz FSB CPU, a motherboard supports 1066MHz(PC2-8500) ram, and some PC2-8500 ram. At default the CPU would be running @ 333MHz FSB (actually frontside bus) and the ram would be running @ 533MHz as long as all values were set correctly in the bios. Your FSB:MEM ratio would be 5:8.

I have no idea what your PC2-6400 would be running at right now, it depends on how your bios is setup and what the SPD of your ram is. Open CPU-Z and check for yourself.

mkk · Jul 15, 2008, 02:53 AM

There's no need to hunt for a 1:1 ratio nowadays as memory and buses are made to run asynchronously. Old truths doesn't always scale up with time.

jepherz · Jul 15, 2008, 06:42 AM

i used CPU-Z, my ram sticks are borrowed from my brothers HP computer. they came stock so they aren't the high quality rams with the heatsink. CPU-Z doesn't reconize it. it knows theres a ram stick in slot 1, but provides no information on it. it says "empty" when i click to view the other 3 slots, so i know its reading it.

the FSB

RAM ratio it shows is 5:6, its supposed to be 5:8? i just clicked "load optimized settings" or whatever in the BIOS...

Lowfat · Jul 15, 2008, 07:39 AM

if your SPD isn't set to PC2-6400, you'll need to set the DRAM ratio yourself.

Jul 14, 2008, 11:31 PM	#1
jepherz HardwareHeaven Lover Join Date: Oct 2004 Posts: 119 Rep Power: 0	ddr2 1:1 ratio? i just saw this while shopping for ram: Newegg.com - OCZ SLI-Ready Edition 2GB (2 x 1GB) 240-Pin DDR2 SDRAM DDR2 1066 (PC2 8500) Dual Channel Kit Desktop Memory - Desktop Memory under customer review the guy says: Pros: As in all matters technical in the universe, there exists a mathematical relationship, a formula if you will, that determines the performance of memory as a component of your communication bus. Your Front Side Bus and Volatile Memory frequencies are usually most efficient and stabile when set at a 1:1 ratio, although some older ram and motherboards actually utilize a 5:4 or 3:2 ratio that is usually not sustainable on Double Data Rate 2 Modules. But how is this 1:1 frequency relationship calculated? There exists a ""Native Bus"" frequency factor that is usually some multiple of an original 33MHz and continuing with 66MHz, 100MHz etc. These settings determine both RAM and Mobo frequency ratings and the relationship between the two is controlled by a factor of 2 (double) for Ram and 4 (quad) for the Front Side Bus. As you can see there is an inherent disproportion between ram and the fsb. When you look at your motherboard's FSB ratings you will generally today see 1066MHz, 1333MHz.....Cons: or 1600MHz capabilties, which when divided by 4 will give you the factor for this ""Native Bus"" which will in turn control the frequency setting of your Ram. As an example...if your Mobo FSB is 1333MHz, then the ""Native Bus"" is (1333/4) = 333.25MHz so your most stabile Ram frequency will now be double that (333.25 x 2) = 666.5 or DDR2-667. Following the above explanation then, if you insert DDR2-1066 modules into Mobo with a 1333MHz FSB, the Mobo will probably utilize this Ram at the lower, but more stabile for data throughput, rating of DDR2-667 as displayed in your system Bios...this is by default. You must ALWAYS overclock the Ram to obtain the higher value....but keep in mind that you will probably have to raise the frequency for the FSB as well in order to maintain that 1:1 ratio for system stability. This is where voltages must be raised as OCZ time and again states in an effort to support the new frequencies...it takes increasing electrical energy to support the ratings.......Other Thoughts: you have raised in your bios or 3rd party tool of choice. I have scored 19820 points in 3DMark06 with an E8400 \| 780i EVGA \| 8800GTS SLI using 4Gb's of this OCZ ram clocked at 939MHz (under 1066MHz) but I had an 1877 (remember 2 x 939) FSB, with the mobo as the limiting factor. That results in a 41% OC on the CPU (1877/4 = 469 fsb so with a Cpu multiplier of 9 (x 469) = 4.22 GHz on a stock 3.0GHz E8400 Intel). And I'm back today to buy more of this Great Ram for a 9950 Phenom build on an MSI K9A2 O/C Mobo...yes its compatible here too. Having said all this...the best advice is that if you are not into overclocking (voids warranties!) then just use the 2 x 4 rule (2x for Ram ~ 4x for FSB) and you will achieve stability and happiness! And.... Oh yeah...you don't look stupid to either the OCZ technical staff...or other 'EggHeads reading your gibberish about how you gotta' dead stick from OCZ...which is really just a random Genetic outcome from my perspective....capish paisano? i have a 1333 fbs mobo and 1066 ram support...what does that mean for me? if i buy 1066 it will run as 667 default and i need to overclock both my ram and mobo for it to work at that speed? is the 1 stick of 800 i have installed right now running at 667?

Jul 15, 2008, 01:37 AM	#2
Lowfat Xtreme Join Date: Oct 2003 Location: Grande Prairie, AB, Can Posts: 4,254 Rep Power: 101	If you have a 1333MHz FSB CPU, a motherboard supports 1066MHz(PC2-8500) ram, and some PC2-8500 ram. At default the CPU would be running @ 333MHz FSB (actually frontside bus) and the ram would be running @ 533MHz as long as all values were set correctly in the bios. Your FSB:MEM ratio would be 5:8. I have no idea what your PC2-6400 would be running at right now, it depends on how your bios is setup and what the SPD of your ram is. Open CPU-Z and check for yourself. __________________

Jul 15, 2008, 06:42 AM	Thread Starter #4
jepherz HardwareHeaven Lover Join Date: Oct 2004 Posts: 119 Rep Power: 0	i used CPU-Z, my ram sticks are borrowed from my brothers HP computer. they came stock so they aren't the high quality rams with the heatsink. CPU-Z doesn't reconize it. it knows theres a ram stick in slot 1, but provides no information on it. it says "empty" when i click to view the other 3 slots, so i know its reading it. the FSBRAM ratio it shows is 5:6, its supposed to be 5:8? i just clicked "load optimized settings" or whatever in the BIOS...

Jul 15, 2008, 07:39 AM	#5
Lowfat Xtreme Join Date: Oct 2003 Location: Grande Prairie, AB, Can Posts: 4,254 Rep Power: 101	if your SPD isn't set to PC2-6400, you'll need to set the DRAM ratio yourself. __________________

Jul 15, 2008, 02:53 AM	#3
mkk Cthulhu/Dagon 2012 Join Date: Oct 2003 Location: Gefle, Sweden Posts: 4,490 Rep Power: 132 System Specs	There's no need to hunt for a 1:1 ratio nowadays as memory and buses are made to run asynchronously. Old truths doesn't always scale up with time.