Memory Clock frequency (basically analog Clock frequency reading)

[ruckb]

Hello, I see that the memory clock frequency readings are "variable". so the change with some number after the decimal point (I do not talk about a "digital" frequency change e. g. from switching from DDR4 2666 to DDR43200).
I guess this number is based on the value fo the BCLK and then some multiplier is used to calculate an exact number (so e. g. 1064,2MHz instad of the official speedgrade with 1067).
My question is: How (and how accurate is the BCLK (or whatever base clock) determined to calculate the exact frequency with even a digit behind the decimal point ?
Just also checked CPU-Z. this one also shows a "uncore Frequency" for my Intel I9-109020X which is switching between 700 and 800MHz (both +/- 2,x MHz)

Thanks for any feedback here..

Hermann

 

[Martin]

Yes, the memory clock is derived from BCLK (so if you overclock BCLK, memory clock is affected as well) and it's as precise as precise the BCLK is. On later Intel CPUs (including yours) the BCLK very precise and provided straight by CPU.

 

[Skylaner]

HI there. I have Lenovo laptop, brand new with 32G DDR4 3200 memory. two 16G sticks. HWiNFO64 seems to correctly say the clock speed is 1596.1. So doubling for the DDR4 would in fact yield about 3200. However, when I run CPU-Z, it says the DRAM frequency is 798. This is half of what WHiFO64 is saying.
The memory should be 3200. That is what was advertised and that is what I paid for and that is what I expect.
What do I really have? Task manager says 3200 but I suspect it is just reading the stick and getting the "marketing" number or doubling the JEDEC numbers. Using shell command and WMIC I also get a speed of 3200 (which I think is just the standard that the stick states).

My concern is whether Lenovo has throttled back the frequency because of heat or other issues and hasn't been up front and expects 99% of purchasers not to know anything about this.

So, my real question is whether I can rely on what HWiNFO64 is showing for the memory clock frequency and that it means the real speed is double that speed because of the DDR.
Am I getting about 3200 if the clock shows 1596.1?

Thanks for any help with this.

 

[Martin]

Which CPU do you have?
It's common for many systems that memory frequency is reduced when system is idle to preserve power. Try under load.

 

[Skylaner]

Hi
I7-11885H Tried under load. Made no difference to the CPU-Z report of 798.
Wonder if something in Lenovo firmware makes it hard for CPU-Z to get right answer????
I am hopeful the memory is running at the "purchased speed" of 3200 (i.e. 1600 per half cycle) but just not sure how to verify given the difference in report between CPU-Z and WHiNFO64 and the results of GeekBench 5 which also claims 798.

Very strange

 

[Martin]

CPU-Z is a different program from a different author and I have no insight into how to reads memory clock, so can't comment on that.

 

[ruckb]

So it seems the accurate value for BCLK and the multiplier is provided / can be read directly from the CPU. Interessting..
@ Skylaner: you can try to limit memory frequency in the BIOS and then check out the reported frequencies and then run benchmarks there you should see a difference in transferrates (at least in real memory benchmarks, maybe not in application benchmarks...)

1600MHz is the Clock Frequency, 3200Mb/s is the transferrate for DDR. even today after >20 Years of DDR memory sometimes people mix up Frequeny and datarate :-(
Especially if you use tools to get Memory speed you might also just get a readout of the SPD data.. but just because the DIMM can handle 3200 the system must not use it, so always figure out if any speed is real system speed or just SPD content..


Hermann

 

[Skylaner]

Hi Hermann,
I remain confused. HWINFO provides good info on my old Dell laptop. Clock speed is about half of the DDR rated speed which makes sense.
HWINFO is also providing me with a clock speed of 1600 which should mean 3200 when doubled. Seems good.

But the other program, CPUZ is showing the clock speed as 798 which means if double, then only getting 1600. That would mean Lenovo would have throttled back the speed perhaps to minimize heat or other failures and did not disclose it to the world. Feels funny that I would have tripped on it.
So I am hoping that CPUZ is not accurate or it is reporting something slightly different.
The Lenovo has not access to the bios to do anything with memory. Totally locked out of that.

Are you aware of any tests that one can run that will show you transfer rates? perhaps that would be instructive?

If Lenovo has governed memory speed, then that is unethical and frankly fraud. I would just send the machine back.
However, the machine appears to be running quite well and in many benchmarks, it does quite good given an I7 with a 3070 graphics card.
But, if memory is throttled, it would do considerably better still. I would have thought a laptop with 32G 3200, Gen 4 SSD, i7 11875 and rtx 3070 card would fair pretty darn good.

ANy further help would be appreciated. No confusion with freq and datarate. a chip with 1600mhz can transfer 3200 mb/s. I am hoping the base freq is 1600 and not 800 as CPU-Z is showing. I like what HWINFO is showing but not sure which one is accurate.

Thanks