Overclock.net › Forums › AMD › AMD - General › Why do AMD Platforms prefer Mhz over timings, etc?
New Posts  All Forums:Forum Nav:

Why do AMD Platforms prefer Mhz over timings, etc?

post #1 of 6
Thread Starter 
Okay, the reason I'm asking this is because I've been screwing with OC's for the past three days. Now, I did tests withing the last hour and a half with a game (BF:BC2).

If you need to know the system I'm doing this on, here goes:

X2 550 BE (Stock, then 3.9Ghz @ 2400Mhz NB)
4GB Ripjaws DDR3 (800, 1600 Mhz)
Radeon HD 4870 1GB (800/1080)


Test 1 (All settings High, 8xAA 16XAF, No HBAO or V-sync - RAM @ 800Mhz 4-5-5-12, CPU @ Stock speeds (3.1Ghz, NB @ 2400Mhz)
Max FPS: 55
Min FPS: 18
Avg FPS: 36

Test 2 (All settings High, as stated above. RAM @ 1600Mhz, 9-9-9-24 timing, CPU @ Stock speed, 2400Mhz NB)
Max FPS: 62
Min FPS: 40
Avg FPS: 51

Test 3 (All settings High, stated above. RAM @ 1600Mhz 9-9-9-24 Timing, CPU @ 3.9Ghz, 2400Mhz NB)
Max FPS: 77
Min FPS: 50
Avg FPS: 63.5


Now what gets me is why Do AMD platforms like Memory/CPU Mhz More than timings? Is it because of the Hypertransport? Is it due to the memory controller?


This is my First AMD/ATI System, so I'm clueless here. I've always used Nvidia/Intel.
post #2 of 6
Any CPU works best with a certain RAM speed grade due to the design of the memory controller. Current CPUs, be that from Intel or AMD prefer DDR3 around 1333-1600 MHz. If it's under 1333 no matter how much you tighten timings, you'll still loose performance. If it's over 1600 you won't gain much and looseining the timings will make you loose performance. As such there is always a sweetspot, for example DDR3 1333 with 7-7-7-21 is similar with DDR3 1600 with 9-9-9-24.

You have tested a far too extreme speed grades with no intermediates, this is why your conclusion is partialy wrong. Keep the CPU/NB speed fixed and do 800, 1066, 1333, 1600, 1866 and keep the lowest possible latencies, you'll find that the sweetspot likely isn't @max MHz with the loosest timings.
Centurion
(14 items)
 
  
CPUMotherboardGraphicsRAM
Phenom II 940 @3.3GHz 1.25V Gigabyte 790X-DS4 XFX 5850 8GB OCZ DDR2-800 
Hard DriveCoolingOSMonitor
Corsair Force 3 TRUE Win 7 Pro x64 ACER 23" TN  
PowerCase
400W Silverstone Strider Antec P182 
  hide details  
Reply
Centurion
(14 items)
 
  
CPUMotherboardGraphicsRAM
Phenom II 940 @3.3GHz 1.25V Gigabyte 790X-DS4 XFX 5850 8GB OCZ DDR2-800 
Hard DriveCoolingOSMonitor
Corsair Force 3 TRUE Win 7 Pro x64 ACER 23" TN  
PowerCase
400W Silverstone Strider Antec P182 
  hide details  
Reply
post #3 of 6
Quote:
If it's under 1333 no matter how much you tighten timings, you'll still loose performance. If it's over 1600 you won't gain much and looseining the timings will make you loose performance.
This is spot on

1600Mhz, as I have observed, is the AMD Phenom II IMC hotspot when it comes to memory bandwidth/latency/performance result.
post #4 of 6
So because 800mhz ram is bottlenecking your PC suddenly AMD prefers higher Mhz than tighter timings? Wrong.
AMDprefer tighter timings at 1333/1600mhz whereas intel ould prefer looser timings at over 1600mhz
    
CPUMotherboardGraphicsRAM
Intel i5 2500k | 4.5Ghz @ uknownV Gigabyte GA-Z68-D3 ASUS EAH6970 | 1000/1300 1.3v 2x2GB Corsair Dominator 1600Mhz 8-8-8 
Hard DriveOSMonitorPower
Samsung Spinpoint F3 500GB Windows 7 Ultimate 64-Bit BenQ G2222HDL + Hanns-G HQ191D Sapphire FirePSU 625w 
Case
GlobalWin YCC-61F1B (Modding planned) 
  hide details  
Reply
    
CPUMotherboardGraphicsRAM
Intel i5 2500k | 4.5Ghz @ uknownV Gigabyte GA-Z68-D3 ASUS EAH6970 | 1000/1300 1.3v 2x2GB Corsair Dominator 1600Mhz 8-8-8 
Hard DriveOSMonitorPower
Samsung Spinpoint F3 500GB Windows 7 Ultimate 64-Bit BenQ G2222HDL + Hanns-G HQ191D Sapphire FirePSU 625w 
Case
GlobalWin YCC-61F1B (Modding planned) 
  hide details  
Reply
post #5 of 6
higher mhz will do the same as tightening your ram at a slower speed


its true ...
My System
(13 items)
 
  
CPUMotherboardGraphicsRAM
FX 8120 Asus crosshair V formula 2 msi HD6870 Twin Frozr II CORSAIR Vengeance 8GB 
Hard DriveOptical DriveOSMonitor
2 SAMSUNG F4 2TB boot + 4 WD 2TB storage Lite On blu ray player win 7 sp1 oem Asus VH236H @ 1920 x 1080 
KeyboardPowerCaseMouse
logitech Media Elite Keyboard ENERMAX MAXREVO 1350W psu SILVERSTONE RAVEN RV02B-EW Matte black logitech OEM 
  hide details  
Reply
My System
(13 items)
 
  
CPUMotherboardGraphicsRAM
FX 8120 Asus crosshair V formula 2 msi HD6870 Twin Frozr II CORSAIR Vengeance 8GB 
Hard DriveOptical DriveOSMonitor
2 SAMSUNG F4 2TB boot + 4 WD 2TB storage Lite On blu ray player win 7 sp1 oem Asus VH236H @ 1920 x 1080 
KeyboardPowerCaseMouse
logitech Media Elite Keyboard ENERMAX MAXREVO 1350W psu SILVERSTONE RAVEN RV02B-EW Matte black logitech OEM 
  hide details  
Reply
post #6 of 6
i made this http://www.overclock.net/amd-cpus/10...-just-fun.html thread few weeks back ,check out the bench marks . in my case i got 1 fps boost from 1333 9-9-9-24mhz to 1600mhz 6-8-6-20
My System
(15 items)
 
  
CPUMotherboardGraphicsRAM
AMD 965 BE @ 3.8ghz ASUS M5A97 R2.0 Sapphire 7870 GHZ Edition  Gskill ripjaws 1600 mhz cl6 ddr3 
Hard DriveHard DriveOptical DriveCooling
Kingston V300 120 GB Seagate 500gb+250gb  LG CM hyper N620 
OSMonitorKeyboardPower
Win 7 UL 64Bit Asus vs247h Logitech G110 Corsair vx 550 
CaseMouseMouse Pad
Zebronics invader Logitech G400 Steel series QCK+ Sk gaming edi 
  hide details  
Reply
My System
(15 items)
 
  
CPUMotherboardGraphicsRAM
AMD 965 BE @ 3.8ghz ASUS M5A97 R2.0 Sapphire 7870 GHZ Edition  Gskill ripjaws 1600 mhz cl6 ddr3 
Hard DriveHard DriveOptical DriveCooling
Kingston V300 120 GB Seagate 500gb+250gb  LG CM hyper N620 
OSMonitorKeyboardPower
Win 7 UL 64Bit Asus vs247h Logitech G110 Corsair vx 550 
CaseMouseMouse Pad
Zebronics invader Logitech G400 Steel series QCK+ Sk gaming edi 
  hide details  
Reply
New Posts  All Forums:Forum Nav:
  Return Home
  Back to Forum: AMD - General
Overclock.net › Forums › AMD › AMD - General › Why do AMD Platforms prefer Mhz over timings, etc?