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ROG Crosshair VIII Formula - Bios set CL15@3600 goes CL16

XIIIIX
Level 7
If i set in bios CL15 @ 3600 and up, it`s showing CL16 CPU-z and other software etc.
Same goes if I reopen Bios @ next boot, and the values are loaded .
If I set it again, no luck CL15 set --> CL16 result

Anyone knows/has this problem?

Have Samsung B-die dual sided 2x 16gB, which can do 1900 CL16 @ 1,425V uncore 1:1
They also do 3466 CL14 and CL15.

Best timings vs. speed so far:

Geheugencontroller ,,,Type Dual Channel (128 bit)
Aktieve modus ,,,Dual Channel (128 bit)

Geheugeninstellingen
CAS Latency (CL) 16T
RAS To CAS Delay (tRCD) 15T
RAS Precharge (tRP) 15T
RAS Active Time (tRAS) 36T
Row Cycle Time (tRC) 60T
Row Refresh Cycle Time (tRFC) 312T, 2x Fine: 486T, 4x Fine: 299T
Command Rate (CR) 1T
RAS To RAS Delay (tRRD) Different Rank: 15T, Same Bank Group: 4T, Diff. Bank Group: 16T
Write Recovery Time (tWR) 16T
Read To Read Delay (tRTR) Different Rank: 4T, Different DIMM: 4T, Same Bank Group: 5T, Diff. Bank Group: 1T
Read To Write Delay (tRTW) 12T
Write To Read Delay (tWTR) 7T, Same Bank Group: 12T, Diff. Bank Group: 6T
Write To Write Delay (tWTW) Different Rank: 6T, Different DIMM: 6T, Same Bank Group: 5T, Diff. Bank Group: 1T
Read To Precharge Delay (tRTP) 12T
Four Activate Window Delay (tFAW) 32T
Write CAS Latency (tWCL) 14T
Write RAS To CAS Delay (tRCDW) 15T
Refresh Period (tREF) 14553T
Idle Cycle Limit 8
Dynamic Idle Cycle Counter Geactiveerd
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16 REPLIES 16

bluestang
Level 7
You can't do odd CAS timings like that on Ryzen. It's a bug. My C15 3600 kit will not do 15-15-15-35, but will do 16-15-15-35.

So eventually I'm just going to try and get 3800 16-16-16-36 to work instead.

Off memory, to do odd CAS settings isnt hard or a bug, find the Gear Down Mode and disabled it (in the manually set timings)

If this does not fix your issue, then post back and I'll refresh my memory / locate the correct setting to change however I'm fairly sure this is the issue fixed.

RedSector73 wrote:
Off memory, to do odd CAS settings isnt hard or a bug, find the Gear Down Mode and disabled it (in the manually set timings)

If this does not fix your issue, then post back and I'll refresh my memory / locate the correct setting to change however I'm fairly sure this is the issue fixed.


It did the trick. C15 is running now @1800 and 1833. 1866 results in a safe boot.
Had to up to 1,435V though for stability.

Time to fine-tune and search the sweet spot.

I tried disabling Gear Down Mode and never got it to work. Maybe upping the volts is the answer, but I didn't want to do that. I'll try it next time I'm tinkering with my system.

XIIIIX wrote:
It did the trick. C15 is running now @1800 and 1833. 1866 results in a safe boot.
Had to up to 1,435V though for stability.
Time to fine-tune and search the sweet spot.


Good to hear that did the trick OP.

For me with a 3900x, 1800 (3600) is the sweet spot. I tested from DDR3200 to 4400 on samsung b-die before settling.

RedSector73 wrote:
Good to hear that did the trick OP.

For me with a 3900x, 1800 (3600) is the sweet spot. I tested from DDR3200 to 4400 on samsung b-die before settling.


@1866 (3733) - Uncore 1:1 @1866 16-16-16-16-36 gives me highest stable clocks and bandwidth, so back to were i came from.
C14 limits @ 3466
C15 limits @ 3633 and lower max core speed ???(45,25 vs 46,75) ???

Timings table:
Geheugeninstellingen
CAS Latency (CL) 16T
RAS To CAS Delay (tRCD) 16T
RAS Precharge (tRP) 16T
RAS Active Time (tRAS) 36T
Row Cycle Time (tRC) 60T
Row Refresh Cycle Time (tRFC) 312T, 2x Fine: 486T, 4x Fine: 299T
Command Rate (CR) 1T
RAS To RAS Delay (tRRD) Different Rank: 16T, Same Bank Group: 4T, Diff. Bank Group: 16T
Write Recovery Time (tWR) 16T
Read To Read Delay (tRTR) Different Rank: 4T, Different DIMM: 4T, Same Bank Group: 5T, Diff. Bank Group: 1T
Read To Write Delay (tRTW) 12T
Write To Read Delay (tWTR) 7T, Same Bank Group: 12T, Diff. Bank Group: 6T
Write To Write Delay (tWTW) Different Rank: 6T, Different DIMM: 6T, Same Bank Group: 5T, Diff. Bank Group: 1T
Read To Precharge Delay (tRTP) 12T
Four Activate Window Delay (tFAW) 32T
Write CAS Latency (tWCL) 16T
Write RAS To CAS Delay (tRCDW) 16T
Refresh Period (tREF) 14553T
Idle Cycle Limit 8
Dynamic Idle Cycle Counter Geactiveerd

try this, I use it on samsung b-die and find it stable 24/7
(however you may have trouble as mine is single rank 8x2 not dual rank <-'assumption' 16x2 b-die sticks)

Memory Frequency [DDR4-3600MHz]
FCLK Frequency [Auto]

CPU SOC Voltage [Manual]
- VDDSOC Voltage Override [1.05000]

DRAM Voltage [1.40000]

DRAM Current Capability [120%]


DRAM CAS# Latency [14]
Trcdrd [15]
Trcdwr [15]
DRAM RAS# PRE Time [15]
DRAM RAS# ACT Time [28]
Trc [42]
TrrdS [6]
TrrdL [8]
Tfaw [16]
TwtrS [4]
TwtrL [12]
Twr [12]
Trcpage [Auto]
TrdrdScl [5]
TwrwrScl [5]
Trfc [288]
Trfc2 [Auto]
Trfc4 [Auto]
Tcwl [16]
Trtp [8]
Trdwr [8]
Twrrd [3]
TwrwrSc [1]
TwrwrSd [7]
TwrwrDd [7]
TrdrdSc [1]
TrdrdSd [5]
TrdrdDd [5]
Tcke [9]
ProcODT [34.3 ohm]
Cmd2T [1T]
Gear Down Mode [Disabled]
Power Down Enable [Disabled]
RttNom [Rtt_Nom Disable]
RttWr [Dynamic ODT Off]
RttPark [RZQ/5]
MemAddrCmdSetup [Auto]
MemCsOdtSetup [Auto]
MemCkeSetup [Auto]
MemCadBusClkDrvStren [30.0 Ohm]
MemCadBusAddrCmdDrvStren [20.0 Ohm]
MemCadBusCsOdtDrvStren [20.0 Ohm]
MemCadBusCkeDrvStren [24.0 Ohm]
Mem Over Clock Fail Count [Auto]


See if this produces better results than your current setup.

84250

https://www.userbenchmark.com/UserRun/25176144
Firestrike - https://www.3dmark.com/3dm/44428278
Skydiver - https://www.3dmark.com/3dm/44428345
Firestrike Ultra - https://www.3dmark.com/3dm/44428627

You could also try Ryzen Dram Calculator
https://www.techpowerup.com/download/ryzen-dram-calculator/

XIIIIX
Level 7
84254

Done it. Best results for my setup as above. (For now)
1 core peaks @4625
2 cores peak @45,75
4 cores peak @44,25
Going more tight, even with lower uncore results in a lower max peak.
1 core @45,75
2 cores @44,25
4 cores @42,50
Usmus1 energy profile.

https://www.userbenchmark.com/UserRun/25428548https://www.userbenchmark.com/UserRun/25428548
https://www.3dmark.com/3dm/44668293?
https://www.3dmark.com/3dm/44668420?
https://www.3dmark.com/3dm/44668798?
https://www.3dmark.com/spy/10914715
https://www.3dmark.com/pr/205275

Nice results, well done OP