1150 DDR2 mem

[toolmaker_03]

Why does the memory at start up read as 1066 memory at 5 5 5 15 when it is 1150 memory?

i can get it to clock to 1165 no problems but why do i have to clock it at all to get the 1150?

 

[Pinhedd]

profiles above DDR2-800 are considered overclocked profiles and need to be configured manually or by using an XMP/EPP profile. The system will never do this automatically for stability reasons

 

[toolmaker_03]

ok think you that helps a lot i plan to clock it futher but i did not know why it would not start up at what i thought was stock settings

 

[Pinhedd]

ok think you that helps a lot i plan to clock it futher but i did not know why it would not start up at what i thought was stock settings

To be honest, DDR2 memory is stupidly hard to overclock because all the memory functions are performed by the northbridge. The NVidia chipsets are the absolute worst and will melt at high frequencies, Intel ones aren't much better.

 

[toolmaker_03]

well my goal is to get it to a core speed of 266 running at 1333 on the mem the whole system is water cooled do you think it is possible?

http://www.tomshardware.com/forum/274855-29-experimental-radiator-build

this is the build

 

[Pinhedd]

Not likely. SDRAM has very little overhead; if it's rated at DDR2-1150 you'll be lucky to get it running at DDR2-1150. I had a hard time getting 4 1GB sticks rated at DDR2-1200 to actually run at DDR2-1200. In another case I couldn't get 4 2GB sticks rated at DDR2-1066 stable at DDR2-1066 and had to fall bck to DDR2-800.

The reason for this is thus:

DDR memory (first generation) has a 2 word prefetch buffer. Each word is transferred across the IO bus on opposite ends of the IO bus clock (this is where the DDR comes from). DDR has performs 1 IO bus clock per memory module clock which results in 2 IO bus transfers per memory clock.

DDR2 memory has a 4 word prefetch buffer. Similarly, there are 2 transfers per IO bus clock which requires 2 bus clocks to transfer all 4 words. DDR2 performs 2 IO bus clocks per memory module clock which results in 4 bus transfers per memory clock.

DDR3 memory has an 8 word prefetch buffer. Similarly, there are 2 transfers per IO bus clock which requires 4 bus clocks to transfer all 8 words. DDR3 performs 4 IO bus clocks per memory module clock which results in 8 bus transfers per memory clock.

What this means is that DDR-400 / PC-3200, DDR2-800 / PC2-6400, and DDR3-1600 / PC3-12800 have 200Mhz,400Mhz, and 800Mhz IO bus reference clocks respectively and a 200Mhz core memory clock commonly.

Similarly, we can see that DDR2-1066 has a core memory clock of 266.5Mhz and DDR3-1066 has a core memory clock of 133.25

DDR2-1333 would require a core memory frequency of 333Mhz, a frequency comparable to DDR3-2666. This is extremely hard to do even on the best motherboards. As far as I know, no DDR2 based motherboards supported anything above DDR2-1200.

Intel's DDR3 controller used in the Sandybridge and Ivybridge processors is much nicer than their old DDR2 controllers but even so, the returns on high-speed SDRAM are barely noticeable.

EDIT: For clarity the core memory speed is not related to the FSB speed. They are two different metrics. Most motherboards derive the memory IO bus speed from the FSB or baseclock and the memory module speed from the IO bus speed. However, some enthusiast motherboards have separate clock generators for the FSB and the memory IO bus

 

[toolmaker_03]

so basicly don't bet on it, but that makes sence, i new that it would be at the top limit of the mem, if posible at all

 

[toolmaker_03]

the memory is ocz flex II 1150MHz it starts up at 1066 all 4 gigs no issues even when clocked to 1165 no issues so i gess i got lucky

 

[Pinhedd]

the memory is ocz flex II 1150MHz it starts up at 1066 all 4 gigs no issues even when clocked to 1165 no issues so i gess i got lucky

DDR2-1066 was amazing. If it runs well at that speed I wouldn't try to push it much farther.

 

[toolmaker_03]

ok i wont push it, is it that easy to damage the memory or is it not that stable?
what types of memory have you tryied meaning the brands i have used OCZ for years the 400DDR pl/rev.2 went to 500 no issues and the 800DDR2 flex I went to 1000 with no issues so i figured that this would at least go to 1200 with no issues.

 

[Pinhedd]

ok i wont push it, is it that easy to damage the memory or is it not that stable?
what types of memory have you tryied meaning the brands i have used OCZ for years the 400DDR pl/rev.2 went to 500 no issues and the 800DDR2 flex I went to 1000 with no issues so i figured that this would at least go to 1200 with no issues.

For the DDR2 platforms its not the memory itself that you need to worry about, it's the memory controller. DDR2 used a very high voltage, I burned out a few NVidia motherboards by running the memory too fast

 

[toolmaker_03]

well it is water cooled to both the NB and SB as well as the mosfets i was not going to push the NB temp past 155 F is that ok?

 

[Pinhedd]

well it is water cooled to both the NB and SB as well as the mosfets i was not going to push the NB temp past 155 F is that ok?

That depends on the chipset, what board are you using?

All the NForce boards I had were completely water cooled, CPU, NB, SB, VRMs, and GPUs with a quad rad and half inch tubing. Barely ever got warm and they still died out.

Intel chips are much better (there's a reason NVidia no longer makes motherboards, they failed at it) but are still vulnerable to the high voltages used by enthusiast DDR2

 

[toolmaker_03]

it is the asus crosshair two mobo it has the voltage switches for all the chips normal, high, and crazy i was hoping to try out the crazy setting but i do not want to burn out my board so i will leave it at high and benchmark at crazy :lol:

** edit did you have a chance to look at the build log go to the last page **

 

[Pinhedd]

Good call. That's some seriously awesome cooling equipment. I love your choice of tubing. I use the same compression fittings in my old PC, they're very snazzy.

 

[toolmaker_03]

thank you it has taken me ten years to build up to this point and there is still so much more i need. i have not had the chance to push the system to far other than to check that it was clockable i took the core clock to 233 with put the mem at 1165 the processor at 3.49 and the ht at 3600 it seemed to boot and run fine at that speed but i have to still run checks to make sure.

 

[toolmaker_03]

Best answer selected by toolmaker_03.