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[RAM & Motherboard] Ram in Bank 2,3 only running at 667Mhz not 800Mhz

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January 4, 2012 6:38:03 PM

Hi Guys

PC componets(Not sure if they are needed)

600w power supply.
Core 2 Deo 2.33Ghz processor
2 x seagate 250GB HDD
RAM Bank 0,1 Kingston DDR2 2GB 800Mhz
RAM Bank 2,3 hynix 2GB 2Rx8 PC2-6400U-666-12
MotherBoard: Jetway BI-210 GeForce7100 / nForce630i
MotherBoard User manual link:

http://www.jetway.com.tw/jw/motherboard_view.asp?produc...


I decided to add a DDR2 RAM chip (hynix 2GB 2Rx8 PC2-6400U-666-12) to my Motherboard(Jetway BI-210 GeForce7100 / nForce630i) in bank 2,3. This motherboard supports 800mhz DDR2 RAM as the RAM in BANK 0,1 runs at 800Mhz. As soon as I add the second RAM Chip to BANK 2,3 the frequancy drops from 800Mhz to 667Mhz at startup. Both chips are detected and there seems to be no option to overclock the RAM to 800Mhz manually in the BIOS.

Any Help will be appriciacted.
a c 328 V Motherboard
January 4, 2012 6:58:24 PM

It looks to me like the Hynix 2Gb 2Rx8 PC2 6400U 666 -12 Memory is 666, so the mobo automatically down clock's the RAM to the lowest frequency.
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January 5, 2012 3:07:09 AM

jaquith said:
Welcome to Tom's Forum! :) 

The Samsung 2Gb 2Rx8 PC2 6400U 666 - 12 is DDR2-666 - http://www.cedarsys.net/cgi-bin/commerce.cgi?preadd=act...

The difference between DDR2-800 and DDR2-666 is ~1%.


Thanls for reply. Fistly I am confused now. I found this online store selling the same product(same part number) with same code detailing it only runs at 667Mhz.
http://www.cedarpc.com/product/5645/Hynix-2Gb-PC2-6400U...

but I downloaded the Part Number decoder from the Hynix site which basicly says that the S6 part in my part name deams it as a 800Mhz ram chip.

So after this I just inserted the Hynix Ram chip into Bank 0,1 and booted and it displays on the startup screen its running at 800Mhz, as soon as I add the second 800Mhz ram chip into bank 2,3 it drops to 667Mhz.

Lastly quick question regarding your statement about 1% diffrance. How is this determined? By what I know the frequancy 800Mhz/667Mhz relates to the spead requests and data will be transfered from and to the RAM chip. After looking at http://en.wikipedia.org/wiki/DDR2_SDRAM I would expect there to be a 10% diffrance preformace wise between 667Mhz and 800Mhz.

Thanks for all the help so far
a c 328 V Motherboard
January 5, 2012 3:16:50 AM

overklog said:
Thanls for reply. Fistly I am confused now. I found this online store selling the same product(same part number) with same code detailing it only runs at 667Mhz.
http://www.cedarpc.com/product/5645/Hynix-2Gb-PC2-6400U...

but I downloaded the Part Number decoder from the Hynix site which basicly says that the S6 part in my part name deams it as a 800Mhz ram chip.

So after this I just inserted the Hynix Ram chip into Bank 0,1 and booted and it displays on the startup screen its running at 800Mhz, as soon as I add the second 800Mhz ram chip into bank 2,3 it drops to 667Mhz.

Lastly quick question regarding your statement about 1% diffrance. How is this determined? By what I know the frequancy 800Mhz/667Mhz relates to the spead requests and data will be transfered from and to the RAM chip. After looking at http://en.wikipedia.org/wiki/DDR2_SDRAM I would expect there to be a 10% diffrance preformace wise between 667Mhz and 800Mhz.

Thanks for all the help so far

The difference shows in the benchmarks, if it would be 20% u still would not be able to tell the differences.
a c 715 V Motherboard
January 5, 2012 11:51:55 AM

Trust me it's <1% difference between DDR2-667 and DDR2-800. There's NO WAY it's 20% - period. Even in DDR3 RAM the differences between DDR3-1333 and DDR3-1866 might be 2-3% on synthetic benchmarks and <1% in all other real world tests; nice article -> http://www.tomshardware.com/reviews/core-i7-870-1156,24...

I looked at your manual, BTW it's worthless, so look for 'Memory Frequency' or 'DRAM Frequency' in the BIOS and change the value to 'DDR2-800MHz'.

Next, since you are clearly Mix-Matching RAM IMO 1. be happy the kits work together at all, 2. increasing the frequency might create an instability.

!