memory speed advice

[RCB03]

Hi all! Thinking about upgrading memory from 256>512Mbs. Currently I am running a GIGABYTE 7VAXP and an Athlon XP 2000+ CPU with OCZ DDR 400(single 256Mb stick). The mother board supports up to 333 Mhz FSB but the processor I have now is only 266 Mhz.The mobo also has dual channel support. What I'm wondering is:

Should I buy another 256Mb DDR 400 module like I have?
Is this memory running in sync with the processor?
Would it be better to go with 2 sticks of PC2100 ( runs at 266Mhz.)

Memory speeds and dual channel support mobos are new to me and reading the PC Guide and the posts in the forum have me wondering if DDR 400 is the wrong memory for my system. What do you think?

[rond36]

I think this post should have been in the Buying and upgrading forum

Your motherboard does not support duel channel DDR!

In fact the Via KT400A chipset does not support duel channel DDR so any board with that chipset does not support it.

If you want a Gigabyte board that supports 400MHz FSB and duel chanel DDR400 get the GA-7N400-L1 (http://www.giga-byte.com/MotherBoard/Products/Products_Spec_GA-7N400-L1.htm).

From the spec sheet for the GA-7N400-L1
Type:Dual Channel DDR400/ 333/ 266- 184pin

Max capacity: Up to 3GB by 4 DIMM slots

From the spec sheet for your board:
Type : DDR400(PC3200)* / DDR333 (PC2700) / DDR266 (PC2100) / DDR200 (PC1600) -184pin
Max capacity : Up to 3GB by 3 DIMM slots

To support duel channel DDR the board needs to have an even number of DIMM slots because you are required to install the DIMMs in pairs for the duel chanel to work.

If your motherboard supported duel channel DDR your computer would not work with only 1 DIMM installed or it would work only in single chanel mode

Here is a list (http://tw.giga-byte.com/MotherBoard/Support/TechnologyGuide/TechnologyGuide_37.htm) of DDR400 memory modules recommended for your motherboard by Gigabyte.

Try to buy good quality RAM like Kingston, Samsung, or Crucial.
Companies like OCZ and Corsair will sell you DDR333 and jack up the price just because they say it will overclock to DDR400 specs. They put heat spreaders on over the chips so you can't read the printing on them and find out they used lower speed chips.

When I built the PC that I am using I bought 768MB (256X3) of Corsair PC2700 (DDR333) CAS2 after I installed it I went onto BIOS setup and the SPD was reading it as PC2100 (DDR266) and CAS3 the DRAM clock was set at 133MHz so I set the DRAM timings at 3:5 that set the DRAM clock to 166MHz (DDR333) and set the CAS to 2 this is the specs Corsair guarantees the Ram to run at. I rebooted but it would not boot up it went into a POST loop. I had to reset the BIOS to get it to stop. I never did get that RAM to run at the advertised speed. I took it out and bought 768MB Samsung PC2700 and the SPD is correct on it at DDR333 CAS2.5 but runs at CAS2 and have run it overclocked to DDR350 (175MHz X 2)

Who wants to buy RAM that you have to overclock just to get it to run at the advertised speed.

It is kind of like going to buy a chevy with a 400 HP engine. The dealer tries to sell you a car with a 350 HP engine. He tells you that you can tune it up to run as fast as a 400 HP and adds $1000 to the price because it can go as fast as a 400 HP. Would you buy it, I wouldn't I would go elsewhere and buy a 400 HP then tune it up to run as fast as a 450 HP.

[Deagle]

Well after what rond36 said I don't know what else to tell you. Your processor is currently not running insync with your ram and I bet your mobo right now is forcing your ram to run at 266mhz. Now you don't have to buy pc2100 ram. What you can do is overclock your processor to run at 333mhz fsb so that your ram will run at its original speed which is 333.:eek:
However overclocking is really DANGEROUS if your not careful or is a newcomer to the subject. The other choice is buy a new processor and I suggest you get the 2500+, it runs at 333mhz fsb.
Cheers:)

[rond36]

I feel the whole thing with the processor and RAM needing to be running at the same speed is not true. My processor runs at 400MHz FSB (100 X 4) and my RAM runs at 333MHz (166 X 2). Almost all motherboards support independant memory timmings. I would run the processor at 266MHz (133 X 2) and the RAM at 400MHz (200 X 2)

[malcore]

I feel the whole thing with the processor and RAM needing to be running at the same speed is not true.

It isn't true if you are running single channel DDR on a P4 system. It is true, however, if you are running dual channel on either a P4 or Athlon system. On a single channel Athlon system, the extra bandwidth from running your RAM faster (async) is not utilized.

On your system rond, you are running your RAM faster than your Processor , 166 over 100, which is good because P4s are bandwidth hungry and will use the extra bandwidth from your RAM.

For a good rundown on RAM and FSB timings, see here (http://www.overclockers.com/tips00157/)

[RCB03]

Sorry about the wrong forum Rond!



What do you think would be the best way to increase memory? Pull the OCZ and install 512Mbs of Crucial Memory or just get another 256Mb stick like I have now. Only bought the OCZ after reading good reviews about it on several different web sites. (I didn't discover The PC Guide until after I had built the pc I have now :mad: ) Thanks for the replies so far!

[drewbob]

There is no need to pull your OCZ memory out. It's not possible for your DDR to be too fast - you can run PC3200 at any speed from 200 to 400mhz. It's just that it costs more to buy fast memory and underclock it.

I would suggest that you buy another stick of PC2700 (DDR333) because it is usually just as cheap as PC2100 and you can always run it at 266 or 333.