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CAS Latency Problem

post #1 of 5
Thread Starter 
Hello.

I overclocked my RAMs and I have a RAM cooler too. I want to set them high clocks (1000 MHz and +). But I can't see Seven (7) CAS Latency Time in Bios. Higher value is 6. You guys can see my computer in my signature.
Edited by Emrets61 - 2/14/12 at 1:49pm
Emre's PC
(15 items)
 
  
CPUMotherboardGraphicsRAM
Intel Core 2 Quad Q9400 Gigabyte GA-P35-DS3 F14 Powercolor ATI Radeon HD5850 PCS+ Corsair XMS2 CM2X1024-6400 - 4 GB (4x1 GB) 
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Samsung 320 GB HD321KJ + Samsung 500 GB HD502HJ LG DVD-RW GH20NS10 Tuniq Tower 120 Extreme Windows 7 Ultimate 64-Bit 
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LG L204WS Logitech Media Keyboard 600 OCZ 600W StealthXStream Logitech Gaming Mouse G500 
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Emre's PC
(15 items)
 
  
CPUMotherboardGraphicsRAM
Intel Core 2 Quad Q9400 Gigabyte GA-P35-DS3 F14 Powercolor ATI Radeon HD5850 PCS+ Corsair XMS2 CM2X1024-6400 - 4 GB (4x1 GB) 
Hard DriveOptical DriveCoolingOS
Samsung 320 GB HD321KJ + Samsung 500 GB HD502HJ LG DVD-RW GH20NS10 Tuniq Tower 120 Extreme Windows 7 Ultimate 64-Bit 
MonitorKeyboardPowerMouse
LG L204WS Logitech Media Keyboard 600 OCZ 600W StealthXStream Logitech Gaming Mouse G500 
Audio
Sharkoon X-Tatic Digital 5.1 
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post #2 of 5
Just to make sure, you realize that lower numbers are better, right?
post #3 of 5
Thread Starter 
Yes. But I'm using Intel CPU and if I read true: high frequency is better than lower timings on Intel CPUs. Now my RAMs running at 880 MHz, 5-5-5-12. I want to set them 1066 or higher at 7-7-7-21. But I can't set it.

Am I doing it right? High frequency or lower timings?
Emre's PC
(15 items)
 
  
CPUMotherboardGraphicsRAM
Intel Core 2 Quad Q9400 Gigabyte GA-P35-DS3 F14 Powercolor ATI Radeon HD5850 PCS+ Corsair XMS2 CM2X1024-6400 - 4 GB (4x1 GB) 
Hard DriveOptical DriveCoolingOS
Samsung 320 GB HD321KJ + Samsung 500 GB HD502HJ LG DVD-RW GH20NS10 Tuniq Tower 120 Extreme Windows 7 Ultimate 64-Bit 
MonitorKeyboardPowerMouse
LG L204WS Logitech Media Keyboard 600 OCZ 600W StealthXStream Logitech Gaming Mouse G500 
Audio
Sharkoon X-Tatic Digital 5.1 
  hide details  
Reply
Emre's PC
(15 items)
 
  
CPUMotherboardGraphicsRAM
Intel Core 2 Quad Q9400 Gigabyte GA-P35-DS3 F14 Powercolor ATI Radeon HD5850 PCS+ Corsair XMS2 CM2X1024-6400 - 4 GB (4x1 GB) 
Hard DriveOptical DriveCoolingOS
Samsung 320 GB HD321KJ + Samsung 500 GB HD502HJ LG DVD-RW GH20NS10 Tuniq Tower 120 Extreme Windows 7 Ultimate 64-Bit 
MonitorKeyboardPowerMouse
LG L204WS Logitech Media Keyboard 600 OCZ 600W StealthXStream Logitech Gaming Mouse G500 
Audio
Sharkoon X-Tatic Digital 5.1 
  hide details  
Reply
post #4 of 5
You've got the right idea, but 1066 at 7-7-7-21 will be slower than 880 5-5-5-12. Though this is a slight oversimplification, CAS latency tells you how many clock cycles it takes the memory to get a memory entry from the time it asks for it. If we do the calculation:

880 million cycles per second / 5 cycles per access = 176 million accesses per second.
1066 million cycles per second / 7 cycles per access = 152 million accesses per second.

Now, if you could achieve 1066 with CAS 6, then we'd be talking. That'd be 177.6 million access per second.

However, there's more to this than just frequency. You also have to take into consideration the frequency of your CPU's FSB. Ideally, you want the ratio to be 1:1, or 1:2, or 1:3, etc. The worst is when you have an almost unity ratio, like 4:5 or 7:8.

Unfortunately, like I said, this is somewhat of an oversimplification. The best way to figure out what is faster is to set the memory to some setting, boot to windows, and then run a benchmark of some kind. Sandra has some great memory benchmarks. You might also want to try running full system benchmarks like 3DMark 11 to test to see if your changes really matter.

The sad truth is that memory frequency and latency doesn't really have much of an effect on system performance. You're talking like 1% at most.
post #5 of 5
Thread Starter 
You explained everything. Thank you very much!
Emre's PC
(15 items)
 
  
CPUMotherboardGraphicsRAM
Intel Core 2 Quad Q9400 Gigabyte GA-P35-DS3 F14 Powercolor ATI Radeon HD5850 PCS+ Corsair XMS2 CM2X1024-6400 - 4 GB (4x1 GB) 
Hard DriveOptical DriveCoolingOS
Samsung 320 GB HD321KJ + Samsung 500 GB HD502HJ LG DVD-RW GH20NS10 Tuniq Tower 120 Extreme Windows 7 Ultimate 64-Bit 
MonitorKeyboardPowerMouse
LG L204WS Logitech Media Keyboard 600 OCZ 600W StealthXStream Logitech Gaming Mouse G500 
Audio
Sharkoon X-Tatic Digital 5.1 
  hide details  
Reply
Emre's PC
(15 items)
 
  
CPUMotherboardGraphicsRAM
Intel Core 2 Quad Q9400 Gigabyte GA-P35-DS3 F14 Powercolor ATI Radeon HD5850 PCS+ Corsair XMS2 CM2X1024-6400 - 4 GB (4x1 GB) 
Hard DriveOptical DriveCoolingOS
Samsung 320 GB HD321KJ + Samsung 500 GB HD502HJ LG DVD-RW GH20NS10 Tuniq Tower 120 Extreme Windows 7 Ultimate 64-Bit 
MonitorKeyboardPowerMouse
LG L204WS Logitech Media Keyboard 600 OCZ 600W StealthXStream Logitech Gaming Mouse G500 
Audio
Sharkoon X-Tatic Digital 5.1 
  hide details  
Reply
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