General question about O'clocking (RAM)

[omega_rugal]

Quote:Does the Ram has to run at 1333Mhz to work properly or is 900Mhz ok?

If the sticker say 1333 the it should run at 1333, if you can only get it to 900 and/or becomes unstable at 1333 then you have been ripped off with defective RAM.

also RAM overclocking is more complicated than CPU overclocking, there are several values that you must adjust and not just "pop up the higher MHz you can"

Quote:Ram overclocking really doesnt give any gains overall.. its so minimal it can be shruged off

True

It`s the last thing you must overclock and only to make the CPU overclock stable.

1- the multiplier
2- the FSB (careful with these as you can make the whole system unstable)
3 - The RAM

[NaturalViolence]

omega_rugal Wrote:If the sticker say 1333 the it should run at 1333, if you can only get it to 900 and/or becomes unstable at 1333 then you have been ripped off with defective RAM.

Not necessarily. The motherboard and/or cpu also need to support it. In this case they do but not in all cases.

Also that's not what he meant. What he was asking is if 1333 MHz ram can be run at 900 MHz without problems. Since his system became unstable when he was OCing unless he popped the ram speed down to 900 MHz.

omega_rugal Wrote:also RAM overclocking is more complicated than CPU overclocking, there are several values that you must adjust and not just "pop up the higher MHz you can"

I disagree. The number of variables to adjust for cpu overclocking is the same or higher unless you count each individual memory latency value as a variable. With memory you really just have ratio, frequency, ram core voltage, IMC voltage, and latency. With cpu overclocking you have several voltages to account for, several clock rates (core, IMC, bus, etc.) to account for, and dozens of important settings that you will have to learn to use if you want to get really serious about it.

omega_rugal Wrote:It`s the last thing you must overclock and only to make the CPU overclock stable.

Memory overclocking will either not impact cpu stability at all or reduce it. Overclocking ram will never improve cpu stability.

omega_rugal Wrote:2- the FSB (careful with these as you can make the whole system unstable)

You're thinking of base clock (BCLK) not FSB.

[omega_rugal]

the GPU on my Llano A8 3570 can easily overclock from 600 to 800 Mhz using 1333 RAM with a rather lineal performance increase, anything above makes the GPU crash. other people using better quality 1866 RAM report it can go as high as 925 MHz with no crashes, and since benchmarks already show that performance of APUs is tightly tied the RAM speed, go figure

after reading the whole thread in detail i think we are mixing some concepts here, could the original poster provide a link to the specific make and model of the RAM in question?

Quote:1333 Mhz

Do you mean DDR3-1333 (without "MHz")

[ExtremeDude2]

(04-23-2013, 06:23 AM)omega_rugal Wrote:

Quote:1333 Mhz

Do you mean DDR3-1333 (without "MHz")

It's the same thing...

[NaturalViolence]

He means DDR3 PC-10666 (also known as PC-10600 and PC-10700). In other words 1333 MT/s. 1333 MT/s ram is always incorrectly marketing as 1333 MHz.

omega_rugal Wrote:the GPU on my Llano A8 3570 can easily overclock from 600 to 800 Mhz using 1333 RAM with a rather lineal performance increase, anything above makes the GPU crash. other people using better quality 1866 RAM report it can go as high as 925 MHz with no crashes,

Just because they happened to be using fast ram in their system doesn't mean that was the reason why they were able to OC higher than you. You need to test it in your system. OC your ram and see if it allows you to OC your IGP higher. Common sense says faster ram isn't going to stabilize a processor. All it's going to do is increase stress on the IMC.

omega_rugal Wrote:and since benchmarks already show that performance of APUs is tightly tied the RAM speed, go figure

IGPs are very memory bandwidth hungry. Their performance does benefit from faster ram but that has nothing to do with their stability.

[omega_rugal]

Quote:OC your ram and see if it allows you to OC your IGP higher

I don`t wanna, besides i would need another mobo, i better get a 1866.

Quote:Just because they happened to be using fast ram in their system doesn't mean that was the reason why they were able to OC higher than you

i beg to differ, a 1866 has been factory tested to be stable at that speed, while 1333 is more prone to fail or corrupt data beyond that point. you must always use the fastest memory you can get when overclocking.

any clue how why 1866 are way more expensive than 1600, 1333 and so on?

http://www.tomshardware.com/reviews/a8-3870k-apu-overclocking-guide,3260.html

Quote:Their performance does benefit from faster ram but that has nothing to do with their stability

at their rated speed yes, but when overclocked, they may starve from memory, either crashing (like my GPU which has to share the memory with the CPU) or performing slower, wasting cycles waiting for data to be ready (a common issue with core 2 cpus)

[NaturalViolence]

omega_rugal Wrote:i beg to differ, a 1866 has been factory tested to be stable at that speed, while 1333 is more prone to fail or corrupt data beyond that point.

Obviously.

Once again you're misunderstanding what I wrote. Although I don't see how since I was directly responding to what you said.

Just because they are using fast ram does not mean that is the reason they were able to OC their cpu/IGP higher than you.

omega_rugal Wrote:you must always use the fastest memory you can get when overclocking.

For performance this may help. But if you just want to raise your core clock rate as high as possible and remain stable it is always recommended to use the slowest memory that you can since faster memory increases stress on the IMC and reduces cpu stability when OCing.

omega_rugal Wrote:at their rated speed yes, but when overclocked, they may starve from memory,

Yes. And like I said this will reduce performance but has nothing to do with stability.

omega_rugal Wrote:either crashing (like my GPU which has to share the memory with the CPU)

Slow memory will never cause a GPU driver to crash or a GPU to become unstable. That's just common sense. Your problem lies elsewhere.

[omega_rugal]

Quote:Just because they are using fast ram does not mean that is the reason they were able to OC their cpu/IGP higher than you.

Quote:Slow memory will never cause a GPU driver to crash or a GPU to become unstable.

Oh boy...

Fine, whatever you say sir...

[NaturalViolence]

You clearly still disagree. Don't just give up. Explain the logic that you have used to arrive at your conclusion and/or provide corroborating evidence.

Please explain to me why slow memory would cause a microprocessor to generate incorrect calculations. Unstable memory could do that. But slow memory? All that's going to do is increase the number of stall cycles. Microprocessors have dynamic stalling logic for a reason.

[omega_rugal]

Quote:slow memory would cause a microprocessor to generate incorrect calculations

high latency memory overclocked (forced) to work faster may lead to that, we are talking about overclocking aren`t we? simply pumping up the RAM clock and/or the voltage without adjusting the RAM timings will either lead to poor performance or crashes due memory corruption.

Quote: All that's going to do is increase the number of stall cycles. Microprocessors have dynamic stalling logic for a reason.

explain that. larger and faster caches prevent stalls but can not do anything once it has happened. what do they do aside from flushing the pipeline, waiting for the data from RAM to be ready and start over?

I`ll get a 1866 RAM and try to get the A8 IGP past the 900 MHz mark