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Best DDR400 / PC3200 Memory for Overclocking

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October 21, 2004 11:20:05 PM

Mobo: A8V Deluxe Wi-Fi.
Processor: Athlon 64 3500+ NewCastle.
Cooling: Stock air cooling.

The motherboard only allows a maximum of DDR400/PC3200 memory speed. Will any memory brands prevent me from overclocking the processor 200Mhz to 300Mhz further, without any memory module changes? If so, can you list a few good DDR400 memory modules to go with to achieve such thing? Thanks in advance.
a b } Memory
a b K Overclocking
October 21, 2004 11:50:14 PM

Crucial Ballistix PC3200 overclocks well beyond DDR500 by increasing the timings and voltage.

But what you're telling us is crap, the board support PC4000, etc. No, it doesn't have a maximum of PC3200, that's just the stock speed.

In fact, Crucial's Ballistix PC3200 and PC4000 are the same thing:

Ballistix PC4000 is set at Cas2.5 by default, so it reaches full rated speed without messing with the timings. It will also run at PC3200 speed, Cas2.

Ballistix PC3200 is set at Cas2 by default, but it will reach PC4000 speed by increasing the timings to Cas2.5.

Physically the modules are the same, the timing differce reflects the way these otherwise identicle modules operate at the two different rated speeds. Your motherboard doesn't differentiate between them, except that it will use the default speed programed on either module.

You could put PC4400 on your board and it would still use it as PC3200.

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October 23, 2004 7:26:06 PM

The official site implies that it can only support DDR400 or slower in dual channel mode. Correct me if I'm wrong, but faster memories aren't supposed to run in single channel mode only?
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a b } Memory
a b K Overclocking
October 23, 2004 8:46:00 PM

OK, you're wrong, but it's only because they aren't telling you what you need to know.

We'll start from the bottom. Say I have a batch of PC3200 and I start testing it to see how far I can push it. Some of the modules run stabley at 205MHz (DDR410), a few run stabley at 210MHz (DDR420), and a few run at 220MHz (DDR440). Since PC3500 speed is DDR433, I take those faster modules and label them PC3500. Does that mean they aren't PC3200? No, it just means that I have PC3200 modules that are able to run faster.

PC3700, PC4000, PC4400 are all doing the same thing, all are PC3200 modules that have the capability of running faster. Some use hand-selected chips, etc, but that doesn't change the fact that they're simply PC3200 modules with a lot of headroom for overclocking.

Consider the Crucial Ballistix PC3200 and PC4000. Say I have a batch of PC3200 modules of very high quality. I take one and test it, the lowest latency it can run at DDR400 is 2-2-2-5, so I call it super low latency, premium PC3200. Say I test it further and find that by loosening the timings to 2.5-3-3-8 I can get the modules up to DDR500. Now I have a choice, label them PC3200 Cas2 or PC4000 Cas2.5. I look at how many of each module type is needed to fill an order and split the batch accordingly. The RAM is all the same!

Say you're planning to overclock. You get PC4000, set it at PC3200 speed, make sure the system runs perfectly, then you can overclock from there.

A problem DOES OCCUR where you can't run dual channel or you can't run at DDR400 on some boards/chipsets, when you're using too many banks of RAM. Some boards will slow down a pair of double sided modules (4-banks), so you're best off with a pair of single sided moduels on those boards. This is significant to A64 chipsets, usually VIA but not excluding nVidia.

To make things even more confusing, Intel chipsets seem to PREFER having more banks, so double sided modules would be better for Intel platforms, worse for AMD platforms.

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October 23, 2004 9:46:27 PM

Let me get this straight - If I get a Ballistix PC4000 and "underclock" it to PC3200 speeds I'll have more room for overclocking than using a standard PC3200 module? And what did you mean by "single" and "double" sided modules? Thanks for replying.
a b } Memory
a b K Overclocking
October 23, 2004 9:55:45 PM

You could get Ballistix PC3200 OR PC4000, the difference between them is the PC3200 is automatically configured as CAS2, while the PC4000 is automatically configured as CAS2.5. If you overclock the PC3200, you'll have to raise the timings manually to CAS2.5. If you overclock the PC4000, it's already pre-set at CAS2.5.

<font color=blue>Only a place as big as the internet could be home to a hero as big as Crashman!</font color=blue>
<font color=red>Only a place as big as the internet could be home to an ego as large as Crashman's!</font color=red>
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