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**parsec** · 09-19-2012, 08:29 PM

Re: CPU-Z reporting to different pc3 memory

Well, given the JEDEC timing values of all the DIMMs, that all have the same part number, DIMMs 1 and 2 match timings, and DIMMs 3 and 4 match timings.

But the JEDEC and XMP timings of DIMMs 1 and 2 do not match the JEDEC and XMP timings of DIMMs 3 and 4! Also, the Max Bandwidth specs of 1 and 2 does not match the Max Bandwidth spec of 3 and 4.

So there are several possibilities here.

If this was a matched set of four DIMMs, all in one package, then G.SKILL packaged them wrong.

If this is two packages of two matched DIMMs, then G.SKILL has changed the specs of this memory between the time you bought the first set of two, and the second set of two.

If you bought them at the same time, you received two different versions of the same part number.

Your board is faithfully running those DIMMs with the different timing information programmed into them, which is interesting, I've never seen that happen. I assume since they are in different channels, each channel can operate at different speeds independently. If you mixed those DIMMs, one of each set in each channel, they would probably run at the lower speed, but might run at the higher speed if you were lucky.

How did you get these identical yet different DIMMs?

**mach1korea** · 09-19-2012, 10:07 PM

Re: CPU-Z reporting to different pc3 memory

there not a matched set of 4 bought 1 month apart from the same supplier. I will try mix and match see if that does anything

**profJim** · 09-20-2012, 12:05 AM

Re: CPU-Z reporting to different pc3 memory

It looks like G.Skill programmed the SPD values differently with your second memory kit.
This might be an error on G.Skill's part or they might have a batch of memory that is mislabeled.
Some motherboards support different memory settings for each memory channel.
In G.SKILL- F3-12800CL9D-4GBNQ memory, your motherboard is not listed in their Qualified Motherboards List.
Their online ram configurator provides a list of recommended memory kits for you motherboard G.SKILL- memory search: ASRock 990FX Extreme4

See if you can exchange both memory kits with a matched set of one of the recommended/tested memory models.

**parsec** · 09-20-2012, 01:47 AM

Re: CPU-Z reporting to different pc3 memory

"Some motherboards support different memory settings for each memory channel."

Really, what is the point of that? To combine different types of memory?

There's all kinds of differences in those DIMMs besides timing data, one set has:

Min Cycle time 1.250 ns (800 MHz)
Min tRP 11.00 ns
Min tRCD 11.00 ns
Min tWR 15.00 ns
Min tRAS 30.00 ns
Min tRC 42.50 ns
Min tRFC 160.13 ns
Min tRTP 7.50 ns
Min tRRD 6.00 ns

The other:

Min Cycle time 1.250 ns (800 MHz)
Min tRP 10.88 ns
Min tRCD 10.88 ns
Min tWR 15.00 ns
Min tRAS 29.63 ns
Min tRC 40.88 ns
Min tRFC 110.00 ns
Min tRTP 7.50 ns
Min tRRD 6.00 ns

We're talking nanoseconds, and fractions of them at that, but the tRFC of 160.13ns in one and 110.00ns in the other could be significant.

I just remembered my X58 mother board uses G.SKILL GBNQ memory, 6 x 2GB DIMMs at 1600, 9 9 9 24 1T. I mixed two, three channel DIMM sets, and they worked fine.

Prof. Jim may be right about the JEDEC and XMP data being programmed wrong on one of those sets.

G.SKILL usually puts the date of manufacture on the label on the DIMMs, my GBNQs have that. You could check if they are far apart in time of manufacture.

If they don't work for you and really are the same part number, I'm sure G.SKILL will RMA your sets and send you matched ones.

**mach1korea** · 09-20-2012, 02:08 AM

Re: CPU-Z reporting to different pc3 memory

I see what you mean but on the Asrock web site they say they are OK ASRock > 990FX Extreme4

**profJim** · 09-20-2012, 02:47 AM

Re: CPU-Z reporting to different pc3 memory

It looks like ASRock tested the memory with your motherboard and G.Skill did not.
The bottom line is that you currently have mismatched memory kits that might lead to lower performance and/or stability issues.
You paid good money for your memory and you shouldn't have to deal with these potential problems.

I never buy memory that is on the motherboard support list as the list is often a small sample of all the memory models in the market.
I always check with the memory manufacturer's tech support to verify which of their kits has been tested with my motherboard.

**mach1korea** · 09-23-2012, 04:00 PM

Re: CPU-Z reporting to different pc3 memory

Over the weekend I played mix and match with them, and found that the new set even a single module would only run at PC3-10700. I will be contacting the supplier today and get exchange.

**mach1korea** · 09-23-2012, 04:03 PM

Re: CPU-Z reporting to different pc3 memory

played around the weekend and found the new set would only work as PC3-10700 even in single channel mode. I will be contacting supplier today.

**parsec** · 09-25-2012, 11:14 PM

Re: CPU-Z reporting to different pc3 memory

Did you try changing the speed of your memory, or is that the default, automatic speed?

As I said I use that model of memory, in an Intel X58 board. Notice the memory has an XMP profile, an Intel memory feature. Now I know memory can be used in Intel or AMD boards, at least in the past, but recently they tend to be more specific about the chipset and CPU manufacture. It seems to me a bit of a stretch to use memory that works in an Intel board with the memory controller on the CPU, and also on AMD hardware.

I would contact G.SKILL, and see what their support people suggest for your board.

Prof. Jim, although your technique of matching memory to a mother board works apparently for you, I don't trust ALL memory manufactures to have competent personnel available to answer questions. Given how many times I have had memory that the manufacture said would work in a certain platform just flat out fail, I live by the QVL list. I may be missing things here, but it has saved me a lot of time and grief, since in my experience, the QVL is always right.

**profJim** · 09-26-2012, 12:08 AM

Re: CPU-Z reporting to different pc3 memory

Originally posted by parsec View Post

Prof. Jim, although your technique of matching memory to a mother board works apparently for you, I don't trust ALL memory manufactures to have competent personnel available to answer questions. Given how many times I have had memory that the manufacture said would work in a certain platform just flat out fail, I live by the QVL list. I may be missing things here, but it has saved me a lot of time and grief, since in my experience, the QVL is always right.

In the past, many memory QVL lists contained a very small sample of tested memory models, and many or most of the listings did not include popular or best selling kits. I like G.Skills approach where they include a list of tested motherboards for each memory kit and they also have an online ram configuration tool that lets you search for compatible memory for your specific motherboard.

If you contact the memory vendor's tech support and ask if memory model XYZ will work with my model ABC motherboard you might not get the correct answer. A better approach would be to ask them to email a list of all tested memory kits that are compatible with your motherboard.

Will the motherboard tech support people help you with settings if the recommended memory doesn't work? Maybe.
Will they help you with memory overclock settings? No.

I have a lot more faith in the memory manufacturer's tech support to help you with your lifetime warrantied memory.

**mach1korea** · 09-26-2012, 07:34 AM

Re: CPU-Z reporting to different pc3 memory

I did but it didn't make any difference changing the timings, the thing is the memory modules I'm using F3-12800CL9-2GBNQ G.Skill are listed on the Asrock QVL but not on the G.skill site for the motherboard.

I did play around with them the weekend and tried them in single channel mode one mudule at a time in the same slot, the original set I bought no problems they showed up as PC3-12800. But the new set just running single channel one module both ot them showed as PC3-10700. I think there is something wrong with them, I have contacted the supplier and they are going to exchange them. ONLY problem is here in Korea it's 'thanks giving' week so there will be a delay.

**parsec** · 09-26-2012, 01:09 PM

Re: CPU-Z reporting to different pc3 memory

There is nothing really wrong with the new set of memory. Modern DRAM memory contains what is called SPD information, which is data in a standard format that is stored in each DIMM, that tells a mother boards BIOS what the memory settings, including speed, the memory will operate at. As we know, your two sets of memory have different SPD data, one set is set to 12800, the other set is set to 10700. You board is simply reading that data and setting the speed to what the data tells it to. Your first post clearly shows the SPD data is different in the two sets of memory you have. Why it is different, we don't know, but it clearly is different.

Your two sets of memory, and your mother board, are all working fine. The problem is the two sets of memory, with the same model number, have different timing and speed data programmed into them. All you need is for the timing and speed data on both sets of memory to be matched at the speed you want (12800), which is not what you have now.

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