Overclock.net › Forums › Components › Memory › Mixed Memory, the conundrum:
New Posts  All Forums:Forum Nav:

Mixed Memory, the conundrum:

post #1 of 7
Thread Starter 
A little memory question:

So I have a Dell Optiplex 755 - intel Q9400, 8 gigs Samsung DDR2 800,
I can overclock (SetFSB) to 3.0 ghz – 3.1 ghz, but that’s about all.
I thought maybe memory.

So, I bought a stick of G. Skill 2 x 2 gig DDR2 1066 to test thinking that that might help - Still no joy.

But:
The Samsung memory I have is 4 x 2 gig, SPD 6, 6, 6, 18, 24 at 400 Mhz
The G. Skill is 1 x 2 gig SPD 6, 6, 6, 18, 24 at 533 Mhz

Sure enough the G.Skil downclocks to 5, 5, 5, 15, 24 at 400 Mhz.
But, since it’s in slot one does that mean the 3 x 2 gigs of Samsung remaining are also at 5, 5, 5, 15, 24 instead of their SPD of 6, 6, 6, 18? I think so!

The conundrum:
Super Pi
4 sticks Samsung 400 23.450
1stick G.Skill 400 + 3 sticks Samsung 400 23.828
Tried Hyper Pi
4 sticks Samsung 400 25.055
1stick G.Skill 400 + 3 sticks Samsung 400 25.261
All are averages of 3 Runs.

Why is Super pi / Hyper pi slower with the lower timings?

I looked a some more timings with Thaiphoon Burner, but I see nothing out of the ordinary.

My System
(15 items)
 
  
CPUMotherboardGraphicsRAM
FX6300 Black M5A99X EVO R2.0 Nvidia GTS450 Team Vulcan PC3 12800 
Hard DriveOptical DriveCoolingOS
Samsung 840 PRO Asus DRW-1608P (x2) Custom Water Cooling Win7 (Ult), Win 8.1 & Win Server 2012 R2 
MonitorKeyboardPowerCase
2 X Samsung 915N Ducky Shine III, Blue Cherry/Blue LEDs PCP&C 1kw Lian Li PC-71 (W/Window) 
MouseAudio
Logiteck G400s none 
  hide details  
Reply
My System
(15 items)
 
  
CPUMotherboardGraphicsRAM
FX6300 Black M5A99X EVO R2.0 Nvidia GTS450 Team Vulcan PC3 12800 
Hard DriveOptical DriveCoolingOS
Samsung 840 PRO Asus DRW-1608P (x2) Custom Water Cooling Win7 (Ult), Win 8.1 & Win Server 2012 R2 
MonitorKeyboardPowerCase
2 X Samsung 915N Ducky Shine III, Blue Cherry/Blue LEDs PCP&C 1kw Lian Li PC-71 (W/Window) 
MouseAudio
Logiteck G400s none 
  hide details  
Reply
post #2 of 7
Thread Starter 
Had a look with Everest.
Same result..............

My System
(15 items)
 
  
CPUMotherboardGraphicsRAM
FX6300 Black M5A99X EVO R2.0 Nvidia GTS450 Team Vulcan PC3 12800 
Hard DriveOptical DriveCoolingOS
Samsung 840 PRO Asus DRW-1608P (x2) Custom Water Cooling Win7 (Ult), Win 8.1 & Win Server 2012 R2 
MonitorKeyboardPowerCase
2 X Samsung 915N Ducky Shine III, Blue Cherry/Blue LEDs PCP&C 1kw Lian Li PC-71 (W/Window) 
MouseAudio
Logiteck G400s none 
  hide details  
Reply
My System
(15 items)
 
  
CPUMotherboardGraphicsRAM
FX6300 Black M5A99X EVO R2.0 Nvidia GTS450 Team Vulcan PC3 12800 
Hard DriveOptical DriveCoolingOS
Samsung 840 PRO Asus DRW-1608P (x2) Custom Water Cooling Win7 (Ult), Win 8.1 & Win Server 2012 R2 
MonitorKeyboardPowerCase
2 X Samsung 915N Ducky Shine III, Blue Cherry/Blue LEDs PCP&C 1kw Lian Li PC-71 (W/Window) 
MouseAudio
Logiteck G400s none 
  hide details  
Reply
post #3 of 7
Thread Starter 
bump
My System
(15 items)
 
  
CPUMotherboardGraphicsRAM
FX6300 Black M5A99X EVO R2.0 Nvidia GTS450 Team Vulcan PC3 12800 
Hard DriveOptical DriveCoolingOS
Samsung 840 PRO Asus DRW-1608P (x2) Custom Water Cooling Win7 (Ult), Win 8.1 & Win Server 2012 R2 
MonitorKeyboardPowerCase
2 X Samsung 915N Ducky Shine III, Blue Cherry/Blue LEDs PCP&C 1kw Lian Li PC-71 (W/Window) 
MouseAudio
Logiteck G400s none 
  hide details  
Reply
My System
(15 items)
 
  
CPUMotherboardGraphicsRAM
FX6300 Black M5A99X EVO R2.0 Nvidia GTS450 Team Vulcan PC3 12800 
Hard DriveOptical DriveCoolingOS
Samsung 840 PRO Asus DRW-1608P (x2) Custom Water Cooling Win7 (Ult), Win 8.1 & Win Server 2012 R2 
MonitorKeyboardPowerCase
2 X Samsung 915N Ducky Shine III, Blue Cherry/Blue LEDs PCP&C 1kw Lian Li PC-71 (W/Window) 
MouseAudio
Logiteck G400s none 
  hide details  
Reply
post #4 of 7
It looks like your memory is running at ~330mhz with the G.Skill, which is probably causing the reduced performance. Also, memory will only run at the speed of the slowest stick present.

Mixing single sticks of memory is never a good thing. With dual channel always at least get your memory in pairs of sticks. If you want more speed, you can try running with 2 bigger sticks rather than 4 smaller ones, as some systems slow down the memory if all the slots are full, look at your manual to see if this is the case.
post #5 of 7
Thread Starter 
Thanks for the coments.

The reason for putting one stick of 1066 memory with 3 sticks of 800 memory is because the timings of the 1066 memory is 5, 5, 5,5, 15 at 800 MHz, . while the timings for the 800 memory is 6,6,6,18.at 800 MHz.

So, with the single stick of 1066 memory in slot 1 all the memory will run at 800 MHz, 5,5,5,15!

As for running larger memory, that's not possible as the motherboard maxes out a 4 x 2 Gigs and that's what's installed.
Your admonition to use matched memory is all well and good, but I'm way beyond doing that.

I'm trying to use the mixing of memory to fool the computer into running the 800 MHz sticks at a lower timings than their SPD tables include And I seem to have succeeded.
The issue is that I'm not seeing the performance increase I should be seeing with the lower timings.

Again, thanks for taking the time to answer - but.

My System
(15 items)
 
  
CPUMotherboardGraphicsRAM
FX6300 Black M5A99X EVO R2.0 Nvidia GTS450 Team Vulcan PC3 12800 
Hard DriveOptical DriveCoolingOS
Samsung 840 PRO Asus DRW-1608P (x2) Custom Water Cooling Win7 (Ult), Win 8.1 & Win Server 2012 R2 
MonitorKeyboardPowerCase
2 X Samsung 915N Ducky Shine III, Blue Cherry/Blue LEDs PCP&C 1kw Lian Li PC-71 (W/Window) 
MouseAudio
Logiteck G400s none 
  hide details  
Reply
My System
(15 items)
 
  
CPUMotherboardGraphicsRAM
FX6300 Black M5A99X EVO R2.0 Nvidia GTS450 Team Vulcan PC3 12800 
Hard DriveOptical DriveCoolingOS
Samsung 840 PRO Asus DRW-1608P (x2) Custom Water Cooling Win7 (Ult), Win 8.1 & Win Server 2012 R2 
MonitorKeyboardPowerCase
2 X Samsung 915N Ducky Shine III, Blue Cherry/Blue LEDs PCP&C 1kw Lian Li PC-71 (W/Window) 
MouseAudio
Logiteck G400s none 
  hide details  
Reply
post #6 of 7
In the 2nd screen-shot you provided, with the 1 stick of G.Skill, the system is running @ DDR2-667 not DDR2-800 like it is with the 4 sticks of Samsung. The performance drop matches pretty closely the difference between the 667 and 800 speeds. I suspect you found a display only bug in the bios or whatever is telling you the system is running at DDR2-800 speeds with the 5-5-5-5-15 timings.
post #7 of 7
Thread Starter 
Quote:
Originally Posted by ShamrockMan View Post

In the 2nd screen-shot you provided, with the 1 stick of G.Skill, the system is running @ DDR2-667 not DDR2-800 like it is with the 4 sticks of Samsung. The performance drop matches pretty closely the difference between the 667 and 800 speeds. I suspect you found a display only bug in the bios or whatever is telling you the system is running at DDR2-800 speeds with the 5-5-5-5-15 timings.

CPU-Z says you're right, nice catch!!

I had put just a single stick of the 1066 memory in to see if it would down clock and it did - to DDR 800.
But alas, adding 800 MHz stick(s) in any slot causes it to down clock to 666 MHz..

Back to the drawing board...............
My System
(15 items)
 
  
CPUMotherboardGraphicsRAM
FX6300 Black M5A99X EVO R2.0 Nvidia GTS450 Team Vulcan PC3 12800 
Hard DriveOptical DriveCoolingOS
Samsung 840 PRO Asus DRW-1608P (x2) Custom Water Cooling Win7 (Ult), Win 8.1 & Win Server 2012 R2 
MonitorKeyboardPowerCase
2 X Samsung 915N Ducky Shine III, Blue Cherry/Blue LEDs PCP&C 1kw Lian Li PC-71 (W/Window) 
MouseAudio
Logiteck G400s none 
  hide details  
Reply
My System
(15 items)
 
  
CPUMotherboardGraphicsRAM
FX6300 Black M5A99X EVO R2.0 Nvidia GTS450 Team Vulcan PC3 12800 
Hard DriveOptical DriveCoolingOS
Samsung 840 PRO Asus DRW-1608P (x2) Custom Water Cooling Win7 (Ult), Win 8.1 & Win Server 2012 R2 
MonitorKeyboardPowerCase
2 X Samsung 915N Ducky Shine III, Blue Cherry/Blue LEDs PCP&C 1kw Lian Li PC-71 (W/Window) 
MouseAudio
Logiteck G400s none 
  hide details  
Reply
New Posts  All Forums:Forum Nav:
  Return Home
  Back to Forum: Memory
Overclock.net › Forums › Components › Memory › Mixed Memory, the conundrum: