HELP G.Skill DDR3 2800 on z77 Formula OC?

[Betty09]

I have tried for around 20 hours to figure out what settings these DIMMs need to be set to in order to POST at their 2800MHZ speed ( 1400 MHZ in CPU Memory Tab ) Here is a bunch of system information in a screenshot. Any help would be great - highest I can get these to POST @ was 2200 Mhz using the settings on their G. Skills website - G.SKILL- World leading DDR3 computer memory and SSD manufacturer -Products

[synack]

Does selecting the XMP profile for 2800 work?

Otherwise slow the timings down. if 11/14/14/35 is the best timing you can get off of 2200Mhz, i would think you are looking at about 14/18/18/40 for 2800.
If that is the case with those latencies, I'm not convinced you be any better off than if you left it at 2200.

Not all RAM has the same compatibility across various motherboards and processors. Your mileage will vary, as will each individual memory stick. When you are pushing components to the max, every tiny flaw is noticeable.
I have learned over the years to ignore manufacturers claims of speed and go with what real people say lol. Generally speaking I find G.skills ratings to be the extreme max, if your really lucky to even get that. Whereas for instance samsung greens are well UNDER rated. you can go well beyond the manufacturers specs. ( I know... I just recently picked up a few sticks and i am amazed at what these things will do.)

Also did you connect ALL motherboard/CPU Power connectors? It really does help stabilize the voltage out. If your PSU is not up to par, you may also be power starved.

As an aside, I would like to mention that having ultra MHz is not what it's all about. the speed of your memory is a combination of MHz and latencies.
Two sticks where one has double the clock but also double the latency is no faster than the other. The faster clocked one will just be waiting around for more cycles.(twice as many in fact)
A rough/easy way I like to compare, is to divide the largest latency into the clock. for example 1100/14 = 78.57. So i call that a "speed" of 78.57. it doesnt mean anything, except as a relative measure against other memory. ie: 1000Mhz 9/10/10/30 memory 1000/10= 100 speed. I would consider the second memory to be about 20-25% faster, even though the clock is slower.
note: don't use the rather large tRAS value as it's a combination of multiple latencies and would complicate the equations.

I use either the raw MHz or the DDR MHz as long as I'm consistent. This is by no way scientific, but it gives me a "quick and dirty" analysis between sticks.

Syn

[Betty09]

Selecting the XMP profile results in a 23 being displayed on Dr. Debug digital board followed by 2 reboots and then when it does boot - its back at DDR3 1600.

[synack]

OK. well if you can't get any better than 14/18/18/40 at 2800, I wouldn't worry about it. If it bothers you, you may try and RMA the memory with G.skill. see if another set of sticks does any better. I don't know if they will take them back or not, as your motherboard isn't in the "tested with" list. I'm pretty sure ASRock won't RMA the motherboard as the memory is not listed in their compatibility list either.

[- wardog -]

In just reading through all 24 pages of THIS thread over at XS, hitting 2800 doesn't bode well in regards to the the 3570K.

[synack]

In just reading through all 24 pages of THIS thread over at XS, hitting 2800 doesn't bode well in regards to the the 3570K.

Yeah, I've been reading some of the same info as well. I have the 3770k so I haven't run into that issue myself. I'm not sure why the 3570 would have issues running the mem overclock as the processors are fairly close... But it is what it is I suppose.
Funny that asrock themselves do list a few 2800 sticks without any mention of requiring a 3770k cpu. I wonder if the 3models they list work with the 3570 at full speed.

[- wardog -]

But it is what it is I suppose.

Unfortunately yes. No guarantees when OC'ing.

Funny that asrock themselves do list a few 2800 sticks without any mention of requiring a 3770k cpu. I wonder if the 3models they list work with the 3570 at full speed.

But here it's the cpu failings/shortcomings. Not the board. No, this here lies on Intel(well, ok. So much as any OC, cpu or mem, is not guaranteed)

Delineating each and every cpu bin/memory combo used would be IMO out of the realm of a MB manufacturers responsibility. Not to mention a sales killer. Consider it akin to why most e-tailers don't respond when asked what bin their current shipping cpus are. I can just imagine the malaise that would create.

To populate the QVL for this board, heck any board, I do not doubt for one second ASRock did not test each listed.

I'd be a kid in a candy store if turned loose in their memory stockpile/bins/shelves.

[- wardog -]

BTW synack. The mathematical formula / essay in post #2?

Some old skool formulas never cease to be applicable. Forgotten or overlooked maybe. Yet always applicable.

[parsec]

This GSKILL memory model is not listed in the boards compatibility list whatsoever, so pure luck if it works at its full speed.

[synack]

BTW synack. The mathematical formula / essay in post #2?

Some old skool formulas never cease to be applicable. Forgotten or overlooked maybe. Yet always applicable.

haha yea. I only mentioned it, as it's a pet peeve of mine. So many manufacturers selling ultra MHz RAM for big dollars, when latency is actually more important! People see "transfer speeds" of 22GB per second and don't realize that is only theoretical and not even remotely possible to obtain. You would need latencies of 1 to reach that bandwidth.


anyway lol