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[Help] Why is the RAM speed only 400MHz instead of 800MHz?

Last response: in Memory
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June 9, 2007 2:47:37 AM

In my sis' PC, 2 pieces each of 1GB DDR2-6400 (800MHz) RAM are installed. But why does Everest show a DDR2-800 (400MHz)?

How do I reset the RAM speed to 800MHz?

--------[ EVEREST Ultimate Edition v4.00 ]-----------------------------------------------------------------------------

Version EVEREST v4.00.976
Benchmark Module 2.1.184.0
Homepage http://www.lavalys.com/
Report Type Quick Report
Computer XXXXXXXXXX
Generator XXXXXXXXXX
Operating System Microsoft Windows Vista Ultimate 6.0.6000 (Vista Retail)
Date 2007-06-09
Time 01:07

--------[ SPD ]---------------------------------------------------------------------------------------------------------

[ DIMM1: Kingston KTC1G-UDIMM ]

Memory Module Properties:
Module Name Kingston KTC1G-UDIMM
Serial Number A83EF481h (2180267688)
Manufacture Date Week 12 / 2007
Module Size 1024 MB (2 ranks, 4 banks)
Module Type Unbuffered DIMM
Memory Type DDR2 SDRAM
Memory Speed DDR2-800 (400 MHz)
Module Width 64 bit
Module Voltage SSTL 1.8
Error Detection Method None
Refresh Rate Reduced (7.8 us), Self-Refresh

Memory Timings:
@ 400 MHz 5-5-5-18 (CL-RCD-RP-RAS) / 23-42-3-6-3 (RC-RFC-RRD-WR-WTR)
@ 266 MHz 4-4-4-12 (CL-RCD-RP-RAS) / 16-28-2-4-2 (RC-RFC-RRD-WR-WTR)
@ 200 MHz 3-3-3-9 (CL-RCD-RP-RAS) / 12-21-2-3-2 (RC-RFC-RRD-WR-WTR)

Memory Module Manufacturer:
Company Name Kingston Technology Company, Inc.
Product Information http://www.kingston.com/products/default.asp

[ DIMM2: Kingston KTC1G-UDIMM ]

Memory Module Properties:
Module Name Kingston KTC1G-UDIMM
Serial Number A93EF781h (2180464297)
Manufacture Date Week 12 / 2007
Module Size 1024 MB (2 ranks, 4 banks)
Module Type Unbuffered DIMM
Memory Type DDR2 SDRAM
Memory Speed DDR2-800 (400 MHz)
Module Width 64 bit
Module Voltage SSTL 1.8
Error Detection Method None
Refresh Rate Reduced (7.8 us), Self-Refresh

Memory Timings:
@ 400 MHz 5-5-5-18 (CL-RCD-RP-RAS) / 23-42-3-6-3 (RC-RFC-RRD-WR-WTR)
@ 266 MHz 4-4-4-12 (CL-RCD-RP-RAS) / 16-28-2-4-2 (RC-RFC-RRD-WR-WTR)
@ 200 MHz 3-3-3-9 (CL-RCD-RP-RAS) / 12-21-2-3-2 (RC-RFC-RRD-WR-WTR)

Memory Module Manufacturer:
Company Name Kingston Technology Company, Inc.
Product Information http://www.kingston.com/products/default.asp

More about : ram speed 400mhz 800mhz

June 9, 2007 3:10:55 AM

Quote:
In my sis' PC, 2 pieces each of 1GB DDR2-6400 (800MHz) RAM are installed.

You mean PC2-6400, which is the same as DDR2-800, which runs at a 400MHz clock (DDR2 stands for Double Data Rate type 2).

Quote:

But why does Everest show a DDR2-800 (400MHz)?

Your screen listings showed only the SPD info, not the actual speed at which the RAM is running.

Check out this post: http://forumz.tomshardware.com/hardware/modules.php?nam...

Bottom line: don't worry, be happy.
June 9, 2007 4:04:29 AM

DDR means Dual Data Rate which means that your effective speed (800MHz) is twice your actual speed (400MHz).
Related resources
June 9, 2007 5:20:50 AM

Becuase the DDR2-800 RAM is running @ 400 Mhz per "dirrection".
DDR1-400 (PC-3200) is running @ 200Mhz per "dirrection".

My DDR1 G.Skill HZ RAM running at 260Mhz per "dirrection" (DDR1-520 T1/CR1 1:1) beats DDR2-800 by far in all Read/Write/Copy/Latency tests on my Optron systems.

Pure raw RAM Mhz is only part of the big picture.

As an example the new DDR3 ram (as it is now) with all it's raw Mhz is crap vs OC'ed high end DDR2.
June 9, 2007 5:58:49 AM

Quote:
You mean PC2-6400, which is the same as DDR2-800, which runs at a 400MHz clock (DDR2 stands for Double Data Rate type 2)


my RAM is PC2-6400 which means it should run at 800MHz but Everest's results show that it's clocking at 400MHz, am I right?
June 9, 2007 6:38:33 AM

No... DDR2-6400 Run at 400mhz. Some stores advertise that its 800mhz since its called DDR2 800, but don't get fooled. DDR2's transfer data on both raise and fall of a clock cycle thus effectively double the speed. So 400mhz DDR2 ram runs effectively as 800mhz, but its actually only running 400mhz internally. Everest's showing result as in the internal mhz which is 400mhz ( thats correct).
June 9, 2007 7:08:18 AM

Ditto
June 9, 2007 8:39:08 PM

Quote:
You mean PC2-6400, which is the same as DDR2-800, which runs at a 400MHz clock (DDR2 stands for Double Data Rate type 2)


my RAM is PC2-6400 which means it should run at 800MHz
As others have pointed out, it's a bit of apples and oranges.
DDR2-800 is the same thing as PC2-6400. Such RAM runs at a memory bus clock speed of 400MHz. However, being a technology (DDR2) that can transfer 2 "chunks" of data per clock cycle, its effective *data rate* is 800MHz.
Bus clock speed and effective data rate are the apples and oranges -- don't confuse them.

Quote:

but Everest's results show that it's clocking at 400MHz, am I right?

No, *your particular* Everest results were not of the section that shows what clock speed the RAM is running at. You posted only the section that shows the SPD data stored in each memory module. See the link in my earlier post (post 2) for details on this.
You can also try running CPU-Z (the "Memory" tab) or PC Wizard 2007 (the "Chipset" section, NOT the "Memory" section) to show the *actual current speed* of your RAM.
!