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I have a Dell Vostro 1000 which uses ATI RS480 mainboard. Specification says that the front bus of such mainboard is 1Ghz.

However, the default RAM came with mainboard is PC4200 (533Mhz).

I wonder if I can replace them with PC6400 (800Mhz) or at least PC5300 (667Mhz)?

Updated: I'm interested in whether the mainboard can recognize and operate the RAM at 800Mhz?

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up vote 1 down vote accepted

The front side bus hasn't been tied to the RAM in a PC for a couple of generations of processor now.

From what I can tell the Vostro 1000 has an AMD Sempron 3600+ or similar processor which as far as I know features an on-chip memory controller, so to determine what memory will work with your machine you should be looking at your processor rather than motherboard. From what I can tell most of those generation of processor can support up to DDR2-800, but without knowing your specific processor (via something like CPU-Z) then it's difficult to say for sure.

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Note that CPU-Z also tells you what memory you can use, not only CPU info. – Gnoupi Apr 1 '10 at 10:03
Am I missing something? I've run up CPU-Z and it tells me what the memory timings are at the moment (memory tab) and what the memory modules themselves are capable of (SPD), but there's no info on what can be fitted that I can see... – Mokubai Apr 1 '10 at 14:17
lshw in Ubuntu reports these information: size: 1700MHz capacity: 4GHz width: 64 bits clock: 200MHz Do these information help? – Phuong Nguyen Apr 3 '10 at 15:45
It should be the processor that matters as to which memory you can use, but I can't find anything other than what Cry Havok suggested in the Crucial Memory Selector that says you will be able to use DDR2-667 memory. In general though one of the ideas of current memory is that higher speed modules should be able work at the speeds of lower modules so in theory a DDR2-800 module would work at 667 in your machine, but I'd trust crucial and just get the DDR2-667 in the first place as they know a lot about memory. – Mokubai Apr 3 '10 at 19:02

Have you tried the Crucial memory selector? It certainly suggests that you can use DDR2-667.

Note too that while faster RAM than a system supports will usually work (in my experience) it'll only run at the speed the system supports. Putting 800 MHz RAM into a system that only supports 533 MHz will result in the system running the RAM at 533 MHz.

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I agree. But how do I know which speed the system support? Because the front bus is at 1Ghz, so any device that doesnot exceed this speed will be fully utilized, right? – Phuong Nguyen Apr 1 '10 at 6:37

Most DDR2 is backwards compatible, but I have never ever been able to get a higher speed of RAM to run when 400MHz is stock from Dell. My experience would suggest that this is the one case where you really need 400MHz.

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So you are saying that the mainboard specification doesn't have any meaning in this case? Presume that this laptop is not from Dell, then will the Mainboard accept and utilize the RAM at RAM full speed (800 Mhz)) – Phuong Nguyen Apr 1 '10 at 3:50
Its might work at 800 Mhz, but they can't guarantee it will work. You would essentially be overclocking you RAM, thus making them warmer than the cooling of your system is designed to cope with. Or it simply won't run at the suggested speed at all due to safety measures of the motherboard. – Ivo Flipse Apr 1 '10 at 6:04

Just be careful I bought some RAM not really sure on the speed of it i guess it was too fast for my computer and after installing all my computer did was BSoD. Seems to me that if a computer runs at a specific speed you shouldnt push it to run faster than that its likely to causes issues.

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