4x2GB 800Mhz Detects as 667Mhz

[brujason]

Hi

Long Story short. I have 2x2GB rams install in my rig and it detected as ADATA DDR2 800Mhz (PC2 6400)
witch is right as a year went by i decided to get another set of 2x2GB Samsung DDR2 800Mhz (PC2 6400) (ADATA not Available anymore at the store) in total now is 8GB (And yes i need 8GB ram video/photo editing my pc is a media server and alot of other stuff)
now BIOS detect the ram as 667Mhz (all 4 RAM's installed)

is this right ? the RAM is different but the same ! one thing i did notice with CPU-Z is the timings are a bit different

ADATA = 5.0 - 5 - 5 - 18 - 23
Samsung = 6.0 - 6 - 6 - 18 - 24 (Can't be a big issue. can it ?)

In BIOS there is this setting under ram overclocking where i can set is to 800Mhz and it boots in to win7x64 and BIOS detect it as 800Mhz is there any harm keeping it on that setting ?
one thing i should mention i had it on that setting for a few day and relized when windows start up and i directly when to opening a video file (.avi .mp4) windows seen to lockup (but when i restart and it desides to open it's open's fast and seeking is also fast) and when it's on 667Mhz(8GB) it seem to open fine but slow and seeking it slow !!

Extra Info
Asus m3n-ht Deluxe (new BIOS)
Phenom II 955 (3.2Ghz)
9800GTX+ SLI (2.0 x16)
750w PSU
SSD 128 GB SATA2 (Did the hole windows7 tweak thing to)
LCD 32" 1080p (DVI-HDMI)

Any reply would be Great (Google let me down on this one)

THX !!

 

[MrUlmo]

I windows sometimes crashes because of the memory running 800mhz, I would find a a livecd with memtest86 or memtest86+, and let it run 2 or 3 time through the entire memory register, if any errors is found, you could tweak the voltages a tiny bit, or let the memory go back to 667mhz ...

 

[jsc]

The timing difference may be a large issue. Set the timing to Samsung 6-6-6-24. Increase the memory voltage to 2.2 volts or "nominal + 0.4 volt". Set the mem clock to 800 MHz and see what happens.

 

[brujason]

Thx for reply !!

No use it keeps giving sluggish performance. I'm just going to buy 2 extra ones
so that i have 4 of the same ram's !!! just one more thing the Samsung ram is the better one here (I'm thinking high means better) ?

 

[brujason]

WTF !! all my research is say the ADATA is better. But it is older then the samsung's
back to the store !!!

 

[jsc]

No. When you are discussing RAM timings, lower is better.

 

[brujason]

THX jsc for the reply
ok got 4 new rams with better timings !!
doing all this research i come across other setting
what is your thoughts on the T1 T2 setting (I might do light OC'ing)