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4GB DDR2 or 3GB DDR3 triple channel?

Last response: in Memory
December 4, 2008 12:33:19 PM

Hi, I am about to take the plunge and upgrade from XP to Vista ultimate 32 bit ( :D  ). I intend to upgrade my PC from socket 939 (4800+/2GB mem) to either nforce7 780i socket 775 with 4GB RAM/Intel Q6600 or maybe the new Corei7 platform (Core i7 920/X58). As I am only upgrading to 32bit Vista (because hardware I will use doesn't support 64bit) I believe I am limited to 4GB RAM so my question is, is it better to have a system with 4GB all in dual channel mode on the 780i platform or 3GB in triple channel mode on the X58 platform? Or can you have 3GB in triple channel and an extra 1GB on the X58 platform?
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December 4, 2008 12:53:04 PM

Some x58 boards run ok in dual channel mode (with 4 sticks of memory and 2 slots left empty). Check the manufacturer's website for recommended brands, and download the motherboard manual before ordering. It only takes a minute to see the memory configuration page. Core i7 runs the memory at 1066, so I wouldn't get 1333 unless you get a great price. I've seen ddr3 as low as $40 a gig recently. I still prefer a ddr2 platform with 4 gigs of memory because of the board and memory prices. Fry's has 4 gigs right now for $39.99 and no rebate. But if you have the money, a low end core i7 and msi board will last longer, but not necessarily give you much better gaming than a comparable 9xxx quad core. Core i7 apparantly shines best when encoding.
December 4, 2008 1:01:54 PM

Honestly I think it is not worth it to go Vista if you don't go 64 bits. What HW do you use which do not support 64 bits (btw, Vista 64 supports 32 bits software so if you can, test your HW on a Vista 64 test system)?

What you could do is have the i7 platform (if it's what you really want) and use 4GB (2x2GB) in dual channel mode then add a 3rd 2GB module when you decide to switch to 64 bits. I saw some reviews showing triple vs dual not that high in real-world benchmarks as the gain in speed seem to be nullified by the extra latency caused.

Also double-check the Ultimate package features, might not be worth it to you as it simply adds the "Business" features to the "Home premium" one.
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December 4, 2008 1:02:17 PM

32 Bit operating systems are able to see (if moded and with a compatible chipset) but unable to allocate more then 2GB of RAM.
"This behavior is due to "memory mapped IO reservations". Those reservations overlay the physical address space and mask out those physical addresses so that they cannot be used for working memory. This is independent of the OS running on the machine.

Significant chunks of address space below 4GB (the highest address accessible via 32-bit) get reserved for use by system hardware:

• BIOS – including ACPI and legacy video support

• PCI bus including bridges etc.

• PCI Express support will reserve at least 256MB, up to 768MB depending on graphics card installed memory "

If u want 4GB or 3GB of ram u should get any modern motherboard/processor and pair it with a 64 Bit Windows.

3GB in triple channel mode on the X58 is faster due less syncronization needed, less memory sticks are always faster if the amount of memory is enought to cover your work - not to mention that triple channel > dual channel (even if not much) and ddr3 > ddr2 (again, even if not much).

If u want triple channel you need three identical sized modules, some chipsets will work with different size modules but the extra memory on the bigger module will not be used. Using 3GB on triple channel plus 1 GB on single channel is possible if the chipset allow it on multiple CPU boards - maybe unggaged mode -, single CPU boards cant do it.
December 4, 2008 1:08:14 PM

Go with 4 on a core2 platform and 3 on a i7 platform.
December 4, 2008 2:55:33 PM

Thanks for the replies, I like the idea of using an i7 board with dual channel then when i upgrade to 64 bit i can slap in the extra RAM in triple channel, maybe 6 x 2GB? The hardware i want to use is a VR headset which I haven't bought yet but they state support for 64 bit vista isn't guaranteed on all titles. I'll be buying the retail version of vista anyway so can upgrade easily once the support is there. It's slightly worrying reading that a 32 bit OS can't allocate more than 2GB RAM however, so does that mean having 4GB in Vista 32 bit is not going to perform better than 2GB?
December 4, 2008 3:29:41 PM

I think the limit is closer to 4GB than 2GB (about 3.5 from what I read in the forum). But yes that means that if your performances will be "capped" for that amount of RAM. If you put 8GB in something that can only "see" 4GB, you will get 4GB performance, the extra will be complete waste.

What is the VR set brand/model (just curious)?
December 6, 2008 1:40:15 AM

Im sorry, my english is very poor so I made it unclear.
32 Bit operating systems can adress 2^32=4096 Mega Bytes but windows 32-bits in particular cannot allocate more then 2GB for a running process.
You can mod windows vista 32 Bit to see all 4GB but like I stated only 2~3 GB will be avaliable for windows to allocate resources for running processes, the other 1~2 GB are reserved for system hardware.