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I wonder, how fast these DDR3 rams can go - G.SKILL Ripjaws X Series F3-14900CL8D-8GBXM:



And what chips they use - so if there is a chance for getting them run faster with more voltage - and what is the safe (or reasonably safe?) voltage limit for them.

That, of course, apply only when the chips used react well to more voltage. So, since the G.Skill logo claims "Go Beyond Limits", then I put these poor rams into Asus Z97-Pro (WiFi ac) board. Upon activating the XMP profile by switch on the board, the rams run at 8-9-9-24 2T @ 1866MHz.

The 2T can be changed to 1T and at that point, it gives with not overclocked i7 4790K, 21 739MB/sec in Memtest 4.20. The voltage is default 1.50V. When tried to set the DDR3-2000MHz memory clock settings, the board failed to post. 1866 seems to be the maximum at such settings (rest is on auto ATM). Precise settings are bellow (most "auto" values report what they are in the bios, what is marked with "???" is not shown up - does not show it's current settig in the bios).

The question is - of course - what best settings to use for these rams (there seems to be plenty of settings, including skews) and what one can expect to get from them on tight timings. Or if relaxing the timings help to get higher and that produce faster result...?
I checked the DDR3 ram chips list there:
http://ramlist.i4memory.com/ddr3/
...yet the closest I found was: PC3-14900 Ripjaws X
F3-14900CL9D-8GBXL (2x4GB) - 9-10-9-28 @ 1.5V - Hynix H5TQ2G83CFR-H9C

Close, but no hit. So that is not exactly helpfull. And since the rams run cold (several memtest hours) at 1.50V, then I believe they might like more voltage
smile.gif
So the question is only how much, or what settings will be optimal to use to get them higher. IIRC the framerate in games stop increasing at about 2100MHz, so reaching the 2000 would be cool.

Is this possible?

The Asus Z97-Pro (WiFi ac) mainboard offer these settings for memory:

Primary Timings
DRAM CAS# Latency [Auto] [1] - [31] - 8
DRAM RAS# to CAS# Delay [1] - [31] - 9
DRAM RAS# PRE Time [Auto] [1] - [31] - 9
DRAM RAS# ACT Time [Auto] [1] - [63] - 24
DRAM Command Rate [Auto] [1] - [2] - 1

Secondary Timings
DRAM RAS# to RAS# Delay [Auto] [1] - [15] - 6
DRAM REF Cycle Time [Auto] [1] - [511] - 243
DRAM Refresh Interval [Auto] [1] - [65535] - 7283
DRAM WRITE Recovery Time [Auto] [1] - [16] - ???
DRAM READ to PRE Time [Auto] [1] - [15] - 8
DRAM FOUR ACT WIN Time [Auto] [1] - [255] - 29
DRAM WRITE to READ Delay [Auto] [1] - [15] - ???
DRAM CKE Minimum Pulse Width [Auto] [1] - [15] - 5
DRAM CAS# Write Latency [Auto] [1] - [31] - 8

RTL IOL control
DRAM RTL Initial Value [Auto] [1] - [63] - Auto
DRAM RTL (CHA_R0D0) [Auto] [1] - [63] - 0
DRAM RTL (CHA_R0D1) [Auto] [1] - [63] - 37
DRAM RTL (CHA_R1D0) [Auto] [1] - [63] - 0
DRAM RTL (CHA_R1D1) [Auto] [1] - [63] - 0
DRAM RTL (CHB_R0D0) [Auto] [1] - [63] - 0
DRAM RTL (CHB_R0D1) [Auto] [1] - [63] - 37
DRAM RTL (CHB_R1D0) [Auto] [1] - [63] - 0
DRAM RTL (CHB_R1D1) [Auto] [1] - [63] - 0
DRAM IO-L (CHA_R0D0) [Auto] [1] - [15] - 0
DRAM IO-L (CHA_R0D1) [Auto] [1] - [15] - 4
DRAM IO-L (CHA_R1D0) [Auto] [1] - [15] - 0
DRAM IO-L (CHA_R1D1) [Auto] [1] - [15] - 0
DRAM IO-L (CHB_R0D0) [Auto] [1] - [15] - 0
DRAM IO-L (CHB_R0D1) [Auto] [1] - [15] - 4
DRAM IO-L (CHB_R1D0) [Auto] [1] - [15] - 0
DRAM IO-L (CHB_R1D1) [Auto] [1] - [15] - 0

Third Timings
tRDRD [Auto] [1] - [7] - 4
tRDRD_dr [Auto] [1] - [15] - 6
tRDRD_dd [Auto] [1] - [15] - 6
tWRRD [Auto] [1] - [63] - 22
tWRRD_dr [Auto] [1] - [15] - 7
tWRRD_dd [Auto] [1] - [15] - 7
tWRWR [Auto] [1] - [7] - 4
tWRWR_dr [Auto] [1] - [15] - 7
tWRWR_dd [Auto] [1] - [15] - 7
Dec_WRD [Auto] [0] [1] - ???
tRDWR [Auto] [1] - [31] - 9
tRDWR_dr [Auto] [1] - [31] - 9
tRDWR_dd [Auto] [1] - [31] - 9

Skew Control
Transmitter Rising Slope [Auto] [0] - [31] - Auto
Transmitter Falling Slope [Auto] [0] - [31] - Auto
Transmitter Control Time [Auto] [0] - [31] - Auto
Receiver Rising Slope [Auto] [0] - [31] - Auto
Receiver Falling Slope [Auto] [0] - [31] - Auto
Receiver Control Time [Auto] [0] - [31] - Auto

MRC Fast Boot [Auto] [Enabled] [Disabled] - Enabled
DRAM CLK Period [Auto] [1] - [14] - Auto
Channel A/B DIMM Control [Enable Both DIMMS] [Disable DIMM0] [Disable DIMM1] [Disable Both DIMMS] - Enable Both DIMMS
Scrambler Setting [Optimized (ASUS] [Default (MRC)] - Optimized (ASUS)
MCH Full Check [Auto] [Enabled] [Disabled] - Auto
 

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Hi there

To be honest OCing ram is time consuming but totally doable
tongue.gif
, now there I G.Skill offer similar ram to the one you own rated up to 2400Mhz, with more voltage of course, so my best guess is that you should try to aim to mimic those specs and see if your system is stable, if not then try changing the timings accordingly, here are the 2 examples:

[RipjawsX] F3-2400C11D-8GXM
DDR3-2400 (PC3-19200)
8GB (4GBx2)
CL11-13-13-31
1.65 Volt

[RipjawsX] F3-17000CL9D-8GBXM
DDR3-2133 (PC3-17000)
8GB (4GBx2)
CL9-11-10-28
1.65 Volt

They use 2T, so keep that in mind.

So like I said try changing your timings to 9-11-10-28 and 1.65v, if you ram is not stable then try losing the timings to 10-11-10-28 and test, if not then bump the voltage a bit more. Try to keep your voltage below 1.7v, that's a maximum safe voltage for 24/7 use. of course it can go over that up to 1.8v+ but i don't recommend that. If you hit 1.72v and your ram is not stable that that speed and Cas, then try losing the timings a bit more, and test. Now if you want to keep your voltage to 1.65v then you should try losing the timings if your OS is not stable, while keeping the same voltage.

You can use, Memtest / IntelBurnTest / Prime95, or a software like that to test your ram speed, and verify stability.

OCing ram speed are not warranted that's why they offer sticks rated for more speed, but I have seen some sticks going from 1333mhz up to 2133Mhz

Hope that helps, Cheers
rolleyes.gif
 
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