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I5 750 CPU memory limitations

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January 6, 2012 6:21:26 PM

Hi there,
Just bought 2 x 4GB DDR3 1600 RAM mods for my ASUS MoBo - their site says it can handle 4x4GB max ... problem however appears related to CPU capacity, where OS is only showing 4GB usable of 8GB ...
I've a 1st Gen i5 750 CPU on deck ... any ideas?
Thanks
a b Ĉ ASUS
a b } Memory
a b V Motherboard
January 6, 2012 11:56:19 PM

your CPU supports up to 16gigs , so does your bios say they are 8gigs? if it does ......are you using a 64-bit OS?
January 7, 2012 3:53:28 PM

hmmm ...

ok, i'm running a ASUS P7P55D, Intel LGA1156 Platform / Intel® P55 Express Chipset
their, website says it supports 16GB - also Crucial website recommends 2 x 4GB DDR3 1600 (when using their tool)

yes, i'm running W7 64-bit Home Premium ed.

i've the latest BIOS installed, although when in BIOS it states 4GB limit, and also 1333 max ... despite ASUS website stating above.

So which is the issue, MoBo or CPU ... or is it me being a muppet ??

Cheers

Related resources
a b Ĉ ASUS
a b } Memory
a b V Motherboard
January 7, 2012 9:31:07 PM

is the memory remaping feature on? if it aint u should check your DIMM slots using CPU-Z if it detects them it might be a bent pin problem
January 9, 2012 7:56:20 PM

you may be onto something, i replaced the original 2 x 2GB mods and the PC came up (eventually)
however, performance has been dire and just cheked perf mon ... only seeing 2 Gigs
Case is open as i type, swapping modules but now can't get the blasted thing to come up ata ll ... :S
January 10, 2012 5:33:56 PM

ok, can't get this damn PC up ... won't get past POST
stripped everything out apart from CPU & Mem, but stopping on RAM check ... this is very strange, is it possible one of the DRAM housings or the memory are at fault?
January 10, 2012 7:38:50 PM

ok, cleaned memory connectors with alcohol wipes - now firing up.
Ran CPU-Z, detected 4GB ... however, BIOS, Perf Mon & Computer properties only showing 2GB ... any ideas?
a c 207 Ĉ ASUS
a b à CPUs
a c 347 } Memory
a c 716 V Motherboard
January 10, 2012 8:06:18 PM

Few possibilities, first look in the BIOS for Memory Remap Feature -> Enabled ; second, what exact set of RAM do you have installed (I need a link) the RAM isn't set per rated. MSCONFIG set with a 4GB limit, it should be set as shown -> http://i1013.photobucket.com/albums/af254/Jaquith/Boot_...

Q - What exact RAM? ; link required

Simplest way to set the RAM with your 2.66GHz CPU:

BIOS:
AI Overclock Tuner -> DOCP
DRAM OC Profile -> DDR3-1600MHz


If you provide the link then I'll add the following...
DRAM Timing Control -> Manual
DRAM CAS# Latency -> ??
DRAM RAS to CAS -> ??
DRAM RAS PRE -> ??
DRAM RAS ACT -> ??

DRAM Timing Mode -> 2N

IMC Voltage -> ??
DRAM Voltage -> ??

Save & Exit = yes

January 10, 2012 8:50:39 PM

Hi Jaqueth

Just what i've been looking for, went into AI Overclock and enabled DOCP - Memory now set at 1600 ... just shoutdown but i think thats due to OC jumper setting req's

MSConfig is as per s/sht

Memory make is - G Skill DDR3 2048 MB PC3-10700H (667Mhz)
F3-12800CL8-2GBRM x 2

Thanks for your help :) 
a c 207 Ĉ ASUS
a b à CPUs
a c 347 } Memory
a c 716 V Motherboard
January 10, 2012 9:08:06 PM

Don't use any Jumpers e.g. DRAM Overvoltage ; use the Normal position OXX (open/closed/closed)

What I found on your RAM:
XMP timings table CL-tRCD-tRP-tRAS-tRC-CR @ frequency (voltage)
XMP #1 8-8-8-24-34-2T @ 800 MHz (1.600 Volts)

Verify with CPU-z 'SPD' tab -> http://www.cpuid.com/softwares/cpu-z.html

BIOS:
AI Overclock Tuner -> DOCP
DRAM OC Profile -> DDR3-1600MHz

If you provide the link then I'll add the following...
DRAM Timing Control -> Manual
DRAM CAS# Latency -> 8
DRAM RAS to CAS -> 8
DRAM RAS PRE -> 8
DRAM RAS ACT -> 24

DRAM Timing Mode -> 2N

IMC Voltage -> 1.30v ; only if needed
DRAM Voltage -> 1.60v

Save & Exit = yes
January 11, 2012 6:38:40 PM

Applied the above settings ... still seeing 2GB of 4GB

Noticed CPU is now runnnig very hot - 85c-90c :??: 

a c 207 Ĉ ASUS
a b à CPUs
a c 347 } Memory
a c 716 V Motherboard
January 11, 2012 7:07:56 PM

None of the above has anything to do with OC'ing.

IMO - Clear CMOS via Jumper method and check temps or at minimum Load Defaults or Load Optimized Defaults. The check the Temps under the same conditions.

Temps right now is a bigger issue.

Q - What HSF are you using?
Q - Is the case full of dust and debris?

Try pulling the side off the case if the temps are still high and post the temp differences between the side ON & OFF.
January 11, 2012 7:29:21 PM

ok, memory detection issue sorted - unseated CPU, blew away some dust!

cpu temp is an issue - there isn't much dust!
just reset bios to DOCP as mem had reverted to 1000mhz, set to 1600 but didn't get to logon - at POST got warning on CPU temp, then dropped out through startup

left idle for 5 mins, started up but still failing to get to windows logon - powers off through startup

January 11, 2012 7:31:39 PM

* using standard edition Intel HSF
January 11, 2012 7:56:06 PM

** Sides are off, averaging 90-95c ... daren't put the sides!
a c 207 Ĉ ASUS
a b à CPUs
a c 347 } Memory
a c 716 V Motherboard
January 11, 2012 8:12:35 PM

If you took off the CPU HSF then you must replace the Thermal Paste, clean the HSF and CPU with Isopropyl alcohol using a lint free towel. Then reapply Thermal paste, I like Arctic Cooling MX-4 - http://www.newegg.com/Product/Product.aspx?Item=N82E168...

The problem is your Thermal Paste. :) 
January 11, 2012 8:15:52 PM

ah ha ... a trip to Novatech then me thinks .... thnx dude :) 
January 14, 2012 5:07:44 PM

Got the paste ....
However, bent pins when reseating CPU, which stopped working - PC went out the window ... nearly :) 
Managed to get them back inline (following 2 x Peroni's to settle the nerves).
CPU now at a comfortable 37c ... and got the 2 x 4GB RAM's up as well
Now @ 8GB running sweet as a nut ... result

Thanks to Jaquith for your knowledge and guidance !!
a c 207 Ĉ ASUS
a b à CPUs
a c 347 } Memory
a c 716 V Motherboard
January 14, 2012 5:14:58 PM

Yeah buddy, I'm sure the bent pins were like a kick in the stomach.

Most importantly, it seems all good! What a ride!
!