Will PC3200 RAM make a difference?
in [Chips]
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From: YKhan on 3 Aug 2005 17:08 Actually, that's not a hard and fast rule about not mixing single-sided and double-sided ram with each other. It really depends on the chipset and BIOS you get. It's a conservative rule, but not a general rule. It does often happen that single- and double-sided ram may cause problems, but the only way you're going to find out if it will cause problems on your system is to actually try it out. You should be able to mix the old 512M DIMM with the new one, but they will both run at the slower stick's speed (lowest common denominator). As for the proper ram speed for a 533Mhz FSB, it actually corresponds to PC2100 (i.e. 533 * 4 = 2132 ~ 2100); while PC3200 corresponds to 800Mhz FSB (800 * 4 = 3200). PC2700 corresponds to a 666Mhz FSB, which Intel just completely skipped, however AMD built processors which corresponded to that speed. Yousuf Khan
From: dk_ on 3 Aug 2005 19:08 In article <1123103339.379432.244490(a)g43g2000cwa.googlegroups.com>, "YKhan" <yjkhan(a)gmail.com> wrote: > Actually, that's not a hard and fast rule about not mixing single-sided > and double-sided ram with each other. It really depends on the chipset > and BIOS you get. It's a conservative rule, but not a general rule. It > does often happen that single- and double-sided ram may cause problems, > but the only way you're going to find out if it will cause problems on > your system is to actually try it out. I read on the Hewlett Packard site, 'not to mix' 8x and 16x for my computer. > You should be able to mix the old 512M DIMM with the new one, but they > will both run at the slower stick's speed (lowest common denominator). If I understand correctly what you explained below, ...running with PC3200 would add no value at all to my machine which has a FSB speed of 533MHz. I understand what you wrote below to mean that no speed above the PC2100 sticks would add any value. ...Right? ;) > As for the proper ram speed for a 533Mhz FSB, it actually corresponds > to PC2100 (i.e. 533 * 4 = 2132 ~ 2100); while PC3200 corresponds to > 800Mhz FSB (800 * 4 = 3200). PC2700 corresponds to a 666Mhz FSB, which > Intel just completely skipped, however AMD built processors which > corresponded to that speed. > > Yousuf Khan > Thanks once again. -Dennis -- Dennis Kessler http://denniskessler.com/acupuncture
From: Yousuf Khan on 4 Aug 2005 00:21 dk_ wrote: > I read on the Hewlett Packard site, 'not to mix' 8x and 16x for my > computer. Well, if it's been specifically written as such, then it must be thus. Usually the suggestion not to mix single-sided and double-sided memory are given anecdotally. For example: Q: "Hi, I'm having trouble with my double-sided ram". A: "Well, your chipset might not be designed for that double-sided memory, switch to single-sided". >>You should be able to mix the old 512M DIMM with the new one, but they >>will both run at the slower stick's speed (lowest common denominator). > > > If I understand correctly what you explained below, ...running with > PC3200 would add no value at all to my machine which has a FSB speed of > 533MHz. > > I understand what you wrote below to mean that no speed above the PC2100 > sticks would add any value. ...Right? ;) It's a little bit more complicated. The memory controller inside your chipset is likely a "dual-channel" controller. That means that it can take two DIMMs and make them act sort of like one faster DIMM. With a single PC2100 DIMM, you're not maxing out your controller; you need two PC2100 DIMMs to max it out. The two PC2100's are sort of combined into a virtual PC4200 (real PC4200's don't actually exist). So a single PC2700 or PC3200 aren't really maxing out your memory controller's maximum bandwidth either, but they're much closer to it than a single PC2100 is. But when you combine a PC2700 and a PC3200, you're not going to get a virtual PC5400 (dual PC2700) let alone a virtual PC5900 (PC2700 + PC3200), you're stuck at a maximum of virtual PC4200 because that's as fast as your FSB will go. As an aside, this is really one of the main advantages to the new AMD64 designs -- they've completely eliminated the FSB, as they've built the memory controller directly into the CPU rather than into the chipset. The memory controller will talk to the rest of the CPU at full internal CPU speeds instead of through the fixed FSB speed. This carries the major advantage of not only increasing the bandwidth but also -- and more importantly -- reducing the latency. Intel is expected to (forced to?) adopt this design by 2007, because it will be four years behind AMD at that point (because AMD will have had this since 2003). Yousuf Khan
From: dk_ on 4 Aug 2005 01:58 In article <hJgIe.5649$z91.624168(a)news20.bellglobal.com>, Yousuf Khan <bbbl67(a)ezrs.com> wrote: > dk_ wrote: > > I read on the Hewlett Packard site, 'not to mix' 8x and 16x for my > > computer. > > Well, if it's been specifically written as such, then it must be thus. > Usually the suggestion not to mix single-sided and double-sided memory > are given anecdotally. For example: > > Q: "Hi, I'm having trouble with my double-sided ram". > > A: "Well, your chipset might not be designed for that double-sided > memory, switch to single-sided". I see. This from the Hewlett Packard site... "The following requirements must be met for the DDR memory to function in Dual Channel mode: * Same Density (128MB, 256MB, 512MB, etc.) * Same DRAM chip technology (x8 or x16) * All either single-sided or dual-sided * Matched in both Channel A and Channel B memory channels" > >>You should be able to mix the old 512M DIMM with the new one, but they > >>will both run at the slower stick's speed (lowest common denominator). I understand. > > If I understand correctly what you explained below, ...running with > > PC3200 would add no value at all to my machine which has a FSB speed of > > 533MHz. > > > > I understand what you wrote below to mean that no speed above the PC2100 > > sticks would add any value. ...Right? ;) > > It's a little bit more complicated. The memory controller inside your > chipset is likely a "dual-channel" controller. That means that it can > take two DIMMs and make them act sort of like one faster DIMM. With a > single PC2100 DIMM, you're not maxing out your controller; you need two > PC2100 DIMMs to max it out. The two PC2100's are sort of combined into a > virtual PC4200 (real PC4200's don't actually exist). So a single PC2700 > or PC3200 aren't really maxing out your memory controller's maximum > bandwidth either, but they're much closer to it than a single PC2100 is. > But when you combine a PC2700 and a PC3200, you're not going to get a > virtual PC5400 (dual PC2700) let alone a virtual PC5900 (PC2700 + > PC3200), you're stuck at a maximum of virtual PC4200 because that's as > fast as your FSB will go. Very clear. Thank you, thank you. ;) > As an aside, this is really one of the main advantages to the new AMD64 > designs -- they've completely eliminated the FSB, as they've built the > memory controller directly into the CPU rather than into the chipset. > The memory controller will talk to the rest of the CPU at full internal > CPU speeds instead of through the fixed FSB speed. This carries the > major advantage of not only increasing the bandwidth but also -- and > more importantly -- reducing the latency. Intel is expected to (forced > to?) adopt this design by 2007, because it will be four years behind AMD > at that point (because AMD will have had this since 2003). > > Yousuf Khan Here's some numbers from an advertisement from e-machine's site... "AMD Athlon 64 3200+ Processor (512KB L2 cache, 2.2GHz, 1600MHz FSB)". The numbers show an FSB speed, (which is much faster than what is advertised in an equivalently priced Celeron D machine. Thanks for the help and education. -Dennis -- Dennis Kessler http://www.denniskessler.com/acupuncture
From: Nate Edel on 4 Aug 2005 02:25
dk_ <nobody(a)spamless.com> wrote: > Here's some numbers from an advertisement from e-machine's site... > "AMD Athlon 64 3200+ Processor (512KB L2 cache, 2.2GHz, 1600MHz FSB)". > > The numbers show an FSB speed, (which is much faster than what is > advertised in an equivalently priced Celeron D machine. That's not the real FSB speed, that's an estimate of the speed of the Hypertransport bus. Athlon 64 3200+ could be either a Socket 939 (dual channel) or Socket 754 chip. Either one has a 200mhz DDR (= "400mhz / DDC 400 / PC3200") FSB to memory. In the case of the Socket 754, that is single channel, while the Socket 939 chip supports dual channel memory so that it's the equivalent of an 800mhz SDR bus (or the QDR 200mhz "800FSB" bus on recent Pentium 4 models, outside of the few 1066FSB EE's) The raw bandwidth on Socket 939 and 800FSB P4s is similar; because of the on-die memory controller, the latency for the AMDs is better. Then again, even with Socket 754 (half the total bandwidth), the latency is better. One other factor with bandwidth is that for the Athlons, there is a separate memory bus (through the on-die controller) and I/O bus with the HT connection[s] to the AGP/PCI/PCI-E slots. On Intel chips, all this bandwidth is shared between the memory and the I/O slots. In practice, I'm not sure if this really makes a difference on single-CPU systems, although having a separate connection for cache coherency and as many memory controllers as there are CPUs definitely cab make a big difference for SMP applications. -- Nate Edel http://www.cubiclehermit.com/ "I do have a cause, though. It is Obscenity. I'm for it." - Tom Lehrer |