Guru3D.com Forums

Go Back   Guru3D.com Forums > Hardware > Die-hard Overclocking & Case Modifications 
Die-hard Overclocking & Case Modifications  Want to overclock that processor, videocard or even mainboard ? Wanna tweak the best out of your piece of hardware or have the means to design a killer case ? Get in here and pimp that rig man.


Reply
 
Thread Tools Display Modes
RAM Timings - tRFC and tRC - whats the difference?
Old
  (#1)
BLEH!
Ancient Guru
 
BLEH!'s Avatar
 
Videocard: 2*7970 @ 1000/1500
Processor: 3930K @ 4.2 GHz, 1.26 V
Mainboard: Gigabyte X79S-UP5
Memory: 16GB@1866MHz@9-10-9-27
Soundcard: Saffire Pro40/KRK Rokit 5
PSU: Enermax Revo 1500W
Default RAM Timings - tRFC and tRC - whats the difference? - 06-16-2011, 23:41 | posts: 4,138 | Location: Not Far North Enough (England)

Hey Gurus

Maybe I'm being a little anal here but I'm doing what many of us do and trying to squeeze every last drop of performance out of my rig. Been faffing with RAM timings and some of the smaller numbers have me confused. I'm familiar with the normal 4 and can't seem to get any tighter where I am now (numbers to follow), but I'm wandering if faffing with any of the other timings with improve performance at all. Looking at CPU-Z though there's an odd thing, it might be a typo, I'm not sure, but I thought it work a check.

Anyway, currently running Corsair Domi (3 x 2 GB) @ 1600 MHz @ 1.7 V. FSB 200 MHz, CPU 4.2 GHz, (x 21 multi), etc.
Timings wise, under the "Memory" tab, this is whats confusing me, in comparison with the "SPD" tab. Highlighted the confusion in bold.
My Memory from the "Memory" Tab:
DRAM Freq: 800.0 MHz
FSBRAM: 2:8
CL: 7.0 clocks
tRCD: 8 clocks
tRP: 7 clocks
tRAS: 20 clocks
Row Refresh Cycle Time tRFC: 88 clocks
CR: 1T

and from the "SPD" Tab, XMP-1600 specs:
Frequency: 800 MHz
CAS# Latency: 7.0
RAS# to CAS#: 8
RAS# Precharge: 7
tRAS: 20
tRC:41
Command Rate: 2T
Voltage: 1.65

I apologise for typing everything but I'm crap with HTML and have no idea how to embed pictures. So my main question is I guess, is tRFC and tRC the same and can I drop the 88 down to 41 in the BIOS for a performance boost?

Either that or does anyone have any mad suggestions for improving performance by tweaking?

Thanks

BLEH!
   
Reply With Quote
 
Old
  (#2)
BLEH!
Ancient Guru
 
BLEH!'s Avatar
 
Videocard: 2*7970 @ 1000/1500
Processor: 3930K @ 4.2 GHz, 1.26 V
Mainboard: Gigabyte X79S-UP5
Memory: 16GB@1866MHz@9-10-9-27
Soundcard: Saffire Pro40/KRK Rokit 5
PSU: Enermax Revo 1500W
Default 06-17-2011, 11:18 | posts: 4,138 | Location: Not Far North Enough (England)

Anyone?
   
Reply With Quote
Old
  (#3)
Mufflore
Ancient Guru
 
Mufflore's Avatar
 
Videocard: KFA2 Anarchy 580@930/4650
Processor: 2500K @ 4.5GHz - blew it!
Mainboard: Gigabyte P67 UD4 B3
Memory: 8G Kngston 2.2GHz CL11 1T
Soundcard: Minimax+ & Dexa Opamps !!
PSU: Corsair Pro AX750
Default 06-17-2011, 11:36 | posts: 9,776 | Location: UK

Here you go, get the fix for your anal issues
http://www.anandtech.com/show/3851/e...fraid-to-ask/3

Basically, memory contents must be refreshed or the data will disappear.
This is done in banks of memory addresses.
The time allowed to complete a refresh of a whole bank is tRFC.
There is some safety margin to make sure that the job is finished so there may be room to tweak.

This statement is key
Quote:
a minimum wait of tRFC cycles is required following a refresh to an idle bank before it can be again activated for access
= from the start of a bank refresh, tRFC cycles are waited before it can be activated again.
   
Reply With Quote
Old
  (#4)
BLEH!
Ancient Guru
 
BLEH!'s Avatar
 
Videocard: 2*7970 @ 1000/1500
Processor: 3930K @ 4.2 GHz, 1.26 V
Mainboard: Gigabyte X79S-UP5
Memory: 16GB@1866MHz@9-10-9-27
Soundcard: Saffire Pro40/KRK Rokit 5
PSU: Enermax Revo 1500W
Default 06-17-2011, 13:13 | posts: 4,138 | Location: Not Far North Enough (England)

Cool, thanks
   
Reply With Quote
 
Old
  (#5)
Messerschmitt
Master Guru
 
Videocard: ASUS 7970 DCU II
Processor: I5 4670K
Mainboard: MSI Z87-G45
Memory: G.Skill 4x4GB DDR1600 CL9
Soundcard: on-board Realtek
PSU: Corsair HX850
Default 05-13-2012, 21:21 | posts: 462

Hi. I'm coming with the same question. Unfortunately I did not really understood Mufflore explanation.

Actually my question is the following:

Should I match the tRFC to the tRC in the SPD table?
So if it says tRC in SPD 33, can I set the tRFC to 33?
If not, how can I find the value?
   
Reply With Quote
Old
  (#6)
TechFreaK
Banned
 
Videocard: GeForce GTX570 Custom OC
Processor: Intel C2Q 8x455Mhz @1.33v
Mainboard: Gigabyte X48-DQ6 @ Turbo
Memory: DDR2 4x 2GB @ 1092mhz
Soundcard: Creative X-FI fatality
PSU: XFX 750W 80+
Default 05-13-2012, 21:59 | posts: 155 | Location: TechLand

^
Hi,

its not the same, tRC is ram's internal timing.

Quote:
-Activate to Precharge delay (tRAS).
Number of clocks taken between a bank active command and issuing the
precharge command. Usually, tRAS=tCL + tRCD + 2.

-Row Cycle Time (tRC).
Determines the minimum number of clock cycles a memory row takes to
complete a full cycle, from row activation up to the precharging of
the active row. For optimal performance, use the lowest value you can,
according to the tRC = tRAS + tRP formula. For example:
if your memory module's tRAS is 7 clock cycles and its tRP is 4 clock cycles,
then the row cycle time or tRC should be 11 clock cycles.

-Refresh to Activate Delay / Refresh Cycle Time (tRFC).
Determines the number of clock measured from a Refresh command (REF)
until the first Activate command (ACT) to the same rank
http://www.tweakers.fr/timings.html#tRC

tRFC affects ram read speed, higher vale = lower read, stabler operation.

Im at 1092mhz - tRFC 82 (default is 70 at 1066mhz or 52 at 800mhz). DDR3 has higher tRFC 90-120+


You can check Aida64 > go to motherboard > chipset >> scroll below for advanced timings. btw those that are missing could be risky, memset 4.1 doesn't show tRC either.

Last edited by TechFreaK; 05-13-2012 at 22:17.
   
Reply With Quote
Old
  (#7)
Messerschmitt
Master Guru
 
Videocard: ASUS 7970 DCU II
Processor: I5 4670K
Mainboard: MSI Z87-G45
Memory: G.Skill 4x4GB DDR1600 CL9
Soundcard: on-board Realtek
PSU: Corsair HX850
Default 05-14-2012, 00:00 | posts: 462

Thanks. So is there a way to tell which is the tRFC number my memory supports? Unfortunately the SPD in CPU-Z does not provide that information
   
Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump



Powered by vBulletin®
Copyright ©2000 - 2014, Jelsoft Enterprises Ltd.
vBulletin Skin developed by: vBStyles.com
Copyright (c) 1995-2014, All Rights Reserved. The Guru of 3D, the Hardware Guru, and 3D Guru are trademarks owned by Hilbert Hagedoorn.