Running at 1:1 Vs using divisor?

[Kamui]

When overclocking, what is the benefit of running your memory at 1:1 versus using a divisor ? I understand that if you have more bandwith at 1:1... but what other benefits are there?

In other words, why would ppl pay so much for a premium 1gb memory when they could very well pay a little more and get a decent 2gb?

 

[Ike0069]

Running 1:1 means the RAM is running at the same speed as the CPU HT (FSB).
Running async (any divider), has shown a loss in performance results. but due mainly to A64's on-die memory controller, the performance loss is small.

Buying value RAM and just running a divider is usually recommended on this board for anyone on a budget.

 

[Bona Fide]

Usually running a divider (when overclocking) means you have more headroom to overclock, and you can keep the memory timings as close to stock as possible. Most people try to find a compromise. I'm running my RAM at DDR470 (235MHz) at 2-3-3-6 timings. Nice overclock and nice timings. 🙂

 

[newParadigm]

My HyperX ram i just got is sweet. Got my DFI NFIIultraB at 260x9.5. Its freekin insane. Got like 1000 extra 3dmarks over my previous 220x11. Although, my fsb AND ram was raised so....that makes more of a difference.

~new

 

[monster64]

Originally posted by: Kamui
When overclocking, what is the benefit of running your memory at 1:1 versus using a divisor ? I understand that if you have more bandwith at 1:1... but what other benefits are there?

In other words, why would ppl pay so much for a premium 1gb memory when they could very well pay a little more and get a decent 2gb?

I don't know what you heard. That is not true at all. The way the a64 memory speed is calculated makes it so that there is so performance loss what so ever. My PC runs alot better at 300x9 w/ a divider of 5/6 to give me 250 mhz for the ram speed. 250x11 (1/1) doesn't run as well even though the divider is 1:1. And BTW, with a divider but running a higher fsb your bandwidth is higher, so I don't know where you heard a divider lowers your bandwidth. Sure, if you fsb stays the same yet you use a divider to lower the ram speed, you bandwidth will drop, but not because of the divider, just because of the lower ram speed in general.

 

[Hacp]

Running the divider doesn't hurt you if thats what your asking. Running the divider for a venice 3000+ to get to 3800+ speeds, you will see NO performance difference between the two chips. Of course, you will see a performance difference if you overclock using the divider vs overclocking running 1:1. Generally, I like 2-2-2-5 memory 🙂.

 

[Kamui]

I see. I think it makes a lot of sense. Thanks for all the info guys.

 

[Powermoloch]

I'm using cheap PqI ddr 400 oc @ 230 mhz 1:1 ratio. stable since then, really really stable 😀

 

[Jeff7181]

Actually 1:1 isn't exactly 1:1. With Athlon 64's, memory speed is derived by dividing the core clock speed of the processor by a number (a whole number, no half numbers). It is not the same as the multiplier used to derive core clock speed from the HTT bus. By coincidence they are the same when running at stock speeds, but that's just because most RAM happens to run at 200 MHz, as does the HTT bus. Which is then multiplied by a 3rd unique multiplier/divider to get the LDT speed. (LDT = Lightning Data Tranport and refers to the bus speed you see advertised as a 1 GHz bus)

For example...

My 3500+ runs at 2200 MHz. The HTT bus runs at 200 MHz and is multiplied by 5 to get the 1000 MHz LDT speed. The HTT bus is also multiplied by 11 to get the 2200 MHz core clock speed. Then since the memory controller is on die and runs at core clock speed, a divider is used, in my case 11, to get the memory speed, 200 MHz. The memory divider can only be whole numbers, unlike the CPU multiplier which can be half numbers as well.

However my CPU is overclocked. It's running at 2500 MHz with the HTT bus at 250, LDT multiplier at 4X, and a memory divider setting of 166 in the BIOS, which corresponds to a 1:12 CPU:RAM ratio, giving me a memory speed of 208 MHz.

 

[newParadigm]

Originally posted by: monster64

Originally posted by: Kamui
When overclocking, what is the benefit of running your memory at 1:1 versus using a divisor ? I understand that if you have more bandwith at 1:1... but what other benefits are there?

In other words, why would ppl pay so much for a premium 1gb memory when they could very well pay a little more and get a decent 2gb?

I don't know what you heard. That is not true at all. The way the a64 memory speed is calculated makes it so that there is so performance loss what so ever. My PC runs alot better at 300x9 w/ a divider of 5/6 to give me 250 mhz for the ram speed. 250x11 (1/1) doesn't run as well even though the divider is 1:1. And BTW, with a divider but running a higher fsb your bandwidth is higher, so I don't know where you heard a divider lowers your bandwidth. Sure, if you fsb stays the same yet you use a divider to lower the ram speed, you bandwidth will drop, but not because of the divider, just because of the lower ram speed in general.

On the original nForceII boards, they wouldn't run an FSB higher than 333, but they would run RAM at 400. If you gave a 6/5 divider, giving a higher RAM speed than FSB. For some reason, it was acutally faster to RUN syncroneous (FSB 333/RAM 333), than async (FSB 333/ RAM 400).

~new