NP5793 Ram speed question

Hey guys, regarding ram speed, I think I have DDR2-667 Mhz but I'm not sure since Everest says I'm running at Real clock (152 Mhz), Effective clock (316 Mhz). Any ideas about this?

I purchased from xoticpc. Thanks!

 

Try using CPU-Z, looks like Everest it´s not reading the speeds correctly on your machine.

About the real and effective clock, it´s because DDR, wich means double data rate. The real clock of any DDR2 667 modules will be 333Mhz, but because it will do two cycles per edge of the digital clock signal(dual-pumped) the effective speed will be twice as fast, wich is 667Mhz.

 

Just being finicky, it'll do one operation per edge, which means two operations per clock cycle. Non DDR SDRAM only performed operations on either the rising or falling clock edge (I can never remember which) and DDR uses both.

 

I spoke with some guys in #fragBU on Enterthegame and they said that the effective clock is 1/2 the marketed clock, this is the I/O clock. Then the memory clock is 1/4 the marketed clock for DDR2 ram. Therefore these frequencies are correct for 667 Mhz ram. Everest also reports the Ram as beig 667 under memory speed in 'SPD' panel.

Basically:
Effective clock = I/O clock = 1/2 DDR2 clock
Real clock = Memory clock = 1/4 DDR2 clock = 1/2 I/O Clock

 

Yes you are correct... my bad... bad translation of my thinking. I was saing edge in a meaning of up and down of the digital signal(0 1 0).

SDR RAM(Single Data Rate) will only make one operation per clock cycle.

 

Nop, on both DDR and DDR2 is used dual pumping, wich means that the real speed will be half the effective.

Ex. on my 667 modules:


Quad pumping is used ex. on CPU´s cache, wich the real speed is 1/4 of the effective.

 

Audigy but thats what I said. Real clock is half of effective clock. The only difference now is naming. Is the effective clock the I/O clock or memory clock? Are you saying that the effective clock = 667 Mhz?

Audigy take a look at the table below.

http://en.wikipedia.org/wiki/DDR2_SDRAM

...................Memory clock......................I/O clock
DDR2-667......166 MHz.........6 ns.............333 MHz.........667 Million............PC2-5300

 

You said:

Effective clock and Input/Output clock are the frequency wich the data is effectively transferend, or the frequency on wich the inputs and outputs occur.

On you case that frequency is 667Mhz.

The real clock is the frequency on wich that cycles occur(rise and fall of the signal is considered one cycle).

Because two data I/O operations occur per cycle, the effective clock will be twice the real one.

 

Ok to clarify, for my ram what do you think the memory clock frequency is? What do you think the I/O clock frequency is?

If I understand you, you are saying the effective clock (or Input and Output clock) is 667 Mhz and the real clock (or Memory clock) is half this or ~333 Mhz.

Is this correct?

 

166MHz

333MHz

I am not sure if the terms 'real' and 'effective' are right, when talking about DRAM. The memory clock has been the same since the SDR RAM era, PC-100/PC-133 - 100MHz/133MHz. Improvements have been made for data transfer rate and bandwidth, whereas the memory clock remained the same for DDR-200/266 and DDR2-400/533.

 

http://www.imagebam.com/image/91238017213790

Heres a link to my everest readings. I think its ok then according to what you are saying. It is DDR-667.

 

333mhz

333mhz

The I/O clock frequency is still 333mhz, but it gets 2 ops per clock so the operation frequency is 667mhz.

yes

correct in thinking, wrong terminology. There is no such thing as SDR RAM (well, there is in your explanation of the acronym, but that acronym is not used)

SDRAM = synchronous dynamic random access memory

therefore we have:

SDRAM = the original
DDR SDRAM = double data rate synchronous dynamic random access memory
DDR2 SDRAM = double data rate (version 2) synchronous dynamic random access memory
DDR3 SDRAM = double data rate (version 3) synchronous dynamic random access memory

Phew!

 

Ok, alright.

I think the screwed up DRAM frequency is because of the Dynamic FSB throttling (95MHz*4 = ~379MHz)

You've got the memory divider there....10/6

So, (10/6)*95 = ~158MHz

158*2 = 316MHz

@theriko: SDR RAM -> Single-Data Rate RAM (It is used quite widely, I guess?)

 

Something like that, yeah...

Just edited my above post to add more info

 

Andy can you explain this memory divider? Also if my memory clock is supposed to be 333 Mhz then obviously im running at much less tan that.

I understand you think the reason for this is dynamic fsb throttling. Where did you get 95Mhz * 4 from? And the 10/6 memory divider? Thanks.

Edit: Oh I See now the 10/6 is the DRAM:FSB ratio. But please explain it more fully.

 

http://en.wikipedia.org/wiki/Memory_divider

Memory divider/multiplier = 10/6 or 1.666666

FSB (real clock)*Memory divider/multiplier = DRAM frequency

95*1.66666 = 158.3333MHz
158*2 = 316MHz

So, RAM is functioning at DDR2-316.

200*1.66666 = 333.333333MHz
333.33333*2 = 667MHz

RAM functions at DDR2-667 at stock.

DRAM frequency (I/O or Real Clock) is directly related to the FSB (real clock)....

 

Something is not correct with your system...

Your FSB was suposed to be 200Mhz, and is set to 95Mhz wich is very weird... 95x4=380 wich means that your FSB it´s working at 380Mhz.

Because the memory frequency is synchronous to FSB, if your FSB it´s working slower the RAM frequency will be lowered too if the FSB:MEM ratio stays the same.

Here is mine VS yours:


As you can see your FSB is working at 379Mhz and your RAM at 316Mhz. Are you sure that your case is not a wrong reading from Everest? Try with version 4.60.1500.

 

The reduced FSB is due to SuperLFM. It scales down FSB from 200 to 100, and the 95-100 is simply due to throttling.

OP: Read the Undervolting Guide, it should clear your doubts, and also how to lock the FSB and CPU frequency to max, but it won't improve performance in any way.

 

Hrm what the hell. I think you are right about the throttling. But one thing that weird is I'm not running any games right now, I opened up everest and it says everything that Audigy's report says. My real clock is at 333, my effective is at 667 same with my fsb (at 200 and 800) now.

This worries me, I hope it is not downclocking during games because when I was running everest while I had Lost planet running in the background (alt-tabbed away from it) it said the same lower specs as before. What do you think Andy?

 

Also, you can try locking the CPU frequency to the highest multiplier using the latest version of RMClock....

CPU-Z doesn't know about SLFM, Everest; Vista and RMClock v2.35, can recognise SLFM.

Its a part of EIST, and won't reduce performance. The FSB and Clock frequency dynamically change according to CPU demand.

If it bothers you alot, you can manually fix a multiplier, which will enable it to run only at a single multiplier, and avoid the downclocking of the clock frequency and FSB/RAM....

It will not downclock during gaming, unless there is no need for the extra CPU power. You can run RMClock in the background and monitor the FID and VID, in the monitoring page in RMClock.

 

No it doesn't bother me at all. The only thing that would is if it was downclocking during gaming. Which according to everest it was, but now it seems locked at full speed, I have yet to see it drop. How does the system detect a game is even initiated? And in turn run at full speed? Thanks!

 

It won't downclock during gaming.
CPU and GPU frequencies downclock only due to excessive heat generation (>100*C).

Use RMClock v2.35 to monitor the frequency as it can detect SLFM too.

CPU frequency will dynamically change during gaming, depending upon CPU usage and demand. Running everest, etc doesn't require CPU power, but the HDD is used, so the CPU downclocks automatically.

You can disable the P-state relating to SLFM in RMClock....

http://www.intel.com/support/processors/sb/CS-028855.htm
http://www.techarp.com/showarticle.aspx?artno=420&pgno=9