Question Not sure what speed to believe

[PsychoCidal]

I've got a z77 Extreme4, i7-2600k (oc-4.6Ghz), 32BG G.Skill Ripjaws X ddr3-2133. My bios lists the memory as 1333mhz and a clock speed of 1.5, but the memory clock in cpuid shows the speed as 1750mhz. Am I looking at the wrong value?

Secondly, I also have four 8gb ddr3-2400 Ripjaw sticks, but my bios only goes up to 2133mhz. Is there a way to manually set the values to reach that speed?

 

[Lutfij]

Welcome to the forums, newcomer!

What BIOS version are you currently on for your motherboard? Got a link to the ram kits you're working with? You need to manually set the speeds within BIOS.

 

[PsychoCidal]

The bios is P2.90

And these are what are in there right now. I've got two of each, in slots 1 and 3, and 2 and 4.

Tomorrow I have four of these coming
Ripjaws Z

 

[hotaru.hino]

Have you loaded the XMP profile in the OC Tweaker page?

 

[Misgar]

At a guess, I'd say your RAM is starting up at the JEDEC default transfer rate of 1333MT/s, i.e. with a true clock speed of 666MHz. Some documentation and utility programs confuse memory transfer rates (measured in MT/s) with clock speed (measured in MHz).

Double Data Rate (DDR) RAM transfers data on the rising and the falling edges of each clock pulse. At stock speeds, your DDR3 RAM will run at 666MHz clock speed, giving an effective transfer rate of 1333 Mega Transfers per second. For DDR, Transfer rate = 2 x Clock speed.

If your CPU and motherboard are capable of higher XMP overclocks, you might be able increase the memory clock speed to 1066MHz, giving an effective transfer rate of 2133MT/s, i.e. DDR3-2133.

If your CPU and motherboard do not allow transfer rates as high as 2133MT/s, you could try 1866MT/s (933MHz clock) or 1600MT/s (800MHz clock).

There is no absolute 100% cast iron guarantee you will be able to achieve 2133MT/s without some manual tweaking in the BIOS.

Best of luck getting your clock rate up to 1200MHz (2400MT/s) with the four new DIMMs. It's generally easier to overclock two DIMMs because they place a lighter load on the Integrated Memory Controller.

Four DIMMs increase memory bus loading, especially if you don't buy a matched set of 4 DIMMs. Two pairs will never be identical in all respects and can lead to instability at high XMP speeds.

 

[Bob.B]

I've got a z77 Extreme4, i7-2600k (oc-4.6Ghz), 32BG G.Skill Ripjaws X ddr3-2133. My bios lists the memory as 1333mhz and a clock speed of 1.5, but the memory clock in cpuid shows the speed as 1750mhz. Am I looking at the wrong value?

Secondly, I also have four 8gb ddr3-2400 Ripjaw sticks, but my bios only goes up to 2133mhz. Is there a way to manually set the values to reach that speed?

Task manager/perf/mem what does it show for speed?

 

[SkyNetRising]

My bios lists the memory as 1333mhz and a clock speed of 1.5, but the memory clock in cpuid shows the speed as 1750mhz. Am I looking at the wrong value?

Can you show screenshots from CPU-Z - memory and spd sections?
(upload to imgur.com and post link)

Note - do not trust values reported by Task Manager. Those often have proved to be unreliable.

 

[PsychoCidal]

Have you loaded the XMP profile in the OC Tweaker page?

The OC tuner set it for me. This is the unmatched set, but the new dimms, coming tomorrow, are all the same. I'll run the tuner again with the new mem and see what it does.

 

[PsychoCidal]

Task manager/perf/mem what does it show for speed?

 

[Bob.B]

That seems to be a match with what the bios is showing.
If you want a 3rd opinion try cpu-z or hwinfo.

 

[PsychoCidal]

Can you show screenshots from CPU-Z - memory and spd sections?
(upload to imgur.com and post link)

Note - do not trust values reported by Task Manager. Those often have proved to be unreliable.

This is with the two slightly mismatched set. Tomorrow I'll have the matched ddr3-2400's in there

 

[PsychoCidal]

This is with the two slightly mismatched set. Tomorrow I'll have the matched ddr3-2400's in there

Here's the 2nd set of dimms

 

[PsychoCidal]

At a guess, I'd say your RAM is starting up at the JEDEC default transfer rate of 1333MT/s, i.e. with a true clock speed of 666MHz. Some documentation and utility programs confuse memory transfer rates (measured in MT/s) with clock speed (measured in MHz).

Double Data Rate (DDR) RAM transfers data on the rising and the falling edges of each clock pulse. At stock speeds, your DDR3 RAM will run at 666MHz clock speed, giving an effective transfer rate of 1333 Mega Transfers per second. For DDR, Transfer rate = 2 x Clock speed.

If your CPU and motherboard are capable of higher XMP overclocks, you might be able increase the memory clock speed to 1066MHz, giving an effective transfer rate of 2133MT/s, i.e. DDR3-2133.

If your CPU and motherboard do not allow transfer rates as high as 2133MT/s, you could try 1866MT/s (933MHz clock) or 1600MT/s (800MHz clock).

There is no absolute 100% cast iron guarantee you will be able to achieve 2133MT/s without some manual tweaking in the BIOS.

Best of luck getting your clock rate up to 1200MHz (2400MT/s) with the four new DIMMs. It's generally easier to overclock two DIMMs because they place a lighter load on the Integrated Memory Controller.

Four DIMMs increase memory bus loading, especially if you don't buy a matched set of 4 DIMMs. Two pairs will never be identical in all respects and can lead to instability at high XMP speeds.

Gotcha. I'll take a slight hit for using both banks.

My mobo allows manual speed up to 2133mhz

I just posted pics showing the JEDEC xfer rate.

 

[PsychoCidal]

At a guess, I'd say your RAM is starting up at the JEDEC default transfer rate of 1333MT/s, i.e. with a true clock speed of 666MHz. Some documentation and utility programs confuse memory transfer rates (measured in MT/s) with clock speed (measured in MHz).

Double Data Rate (DDR) RAM transfers data on the rising and the falling edges of each clock pulse. At stock speeds, your DDR3 RAM will run at 666MHz clock speed, giving an effective transfer rate of 1333 Mega Transfers per second. For DDR, Transfer rate = 2 x Clock speed.

If your CPU and motherboard are capable of higher XMP overclocks, you might be able increase the memory clock speed to 1066MHz, giving an effective transfer rate of 2133MT/s, i.e. DDR3-2133.

If your CPU and motherboard do not allow transfer rates as high as 2133MT/s, you could try 1866MT/s (933MHz clock) or 1600MT/s (800MHz clock).

There is no absolute 100% cast iron guarantee you will be able to achieve 2133MT/s without some manual tweaking in the BIOS.

Best of luck getting your clock rate up to 1200MHz (2400MT/s) with the four new DIMMs. It's generally easier to overclock two DIMMs because they place a lighter load on the Integrated Memory Controller.

Four DIMMs increase memory bus loading, especially if you don't buy a matched set of 4 DIMMs. Two pairs will never be identical in all respects and can lead to instability at high XMP speeds.

 

[SkyNetRising]

Gotcha. I'll take a slight hit for using both banks.
My mobo allows manual speed up to 2133mhz
I just posted pics showing the JEDEC xfer rate.

Get XMP settings from slower module and input them manually.
Latencies 11-13-13-31,
DDR voltage 1.6V (might be necessary to increase to 1.65V),
Command rate 2T,
Frequency 2133mhz.

 

[PsychoCidal]

Get XMP settings from slower module and input them manually.
Latencies 11-13-13-31,
DDR voltage 1.6V (might be necessary to increase to 1.65V),
Command rate 2T,
Frequency 2133mhz.

Since I'm getting the other dimms tomorrow, I'll do everything then. Do you have settings for 2400mhz sticks, or is 2133 about as fast as I'll get.

 

[PsychoCidal]

I've got the 2400mhz dimms on board now. Can I squeeze some performance out of these?

 

[gskill support]

'Load XMP Setting' is set to AUTO, and it doesn't seem like any changes have been made so you need to try one of the profiles to see if it can be stable. DDR3-2400 likely will not be stable so you need to manually reduce to DDR3-2133 or lower to see what can work first.

The main BIOS page where you are looking at DDR3-1333 is not showing live values. CPUz > Memory > DRAM Frequency will show the live bus frequency and timings so you can use this to check changes.

Test for the highest stable DRAM Frequency for each combination and that can provide some insight to system capabilities.

There is a newer BIOS version as well so that is something to consider if necessary.