Will PC3200 RAM make a difference?
in [Chips]
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From: YKhan on 4 Aug 2005 08:41 dk_ 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 a "little white marketing lie". Since most people are used to seeing a FSB speed rating, Emachines just took the closest thing they could find to a front-side bus, which is the Hypertransport link, and called it the FSB. The more proper answer to what is the FSB speed of an AMD64 processor would be "not applicable", but of course that would generate questions like "why is it not applicable?", or "if it doesn't have a FSB, then how does it work?", etc. The Hypertransport link does fulfill one of the functions of the traditional FSB, which is that it connects the i/o chipset to the CPU. However, the memory controller is not on the i/o chipset like with Intels, the memory controller is inside the AMD CPU, so the only job an AMD i/o chipset does is interface with peripheral devices like video cards, hard disks, USB, etc. The AMD memory controller is not part of the Hypertransport connection, it is its own independent connection. That's why AMD has coined the marketing term "Direct Connect Archictecture" to describe the combination of its internal memory controller, and the Hypertransport link. Also Hypertransport is not a bus in the strict sense of the word, it is a point-to-point link, i.e. one-to-one only. Secondly, the speed rating given to it in the ad, "1600MHz FSB", is just a maximum possible speed; the HT link being point-to-point is a negotiated speed. So it only connects at the highest speed common to the CPU and the chipset it is connecting to. If the chipset can only go as fast as 1066MHz, then that's the speed of the HT link that they will negotiate. Yousuf Khan
From: George Macdonald on 4 Aug 2005 16:29 On Wed, 03 Aug 2005 13:29:03 -0700, dk_ <nobody(a)spamless.com> wrote: >In article <1123098915.638307.151670(a)g47g2000cwa.googlegroups.com>, > "YKhan" <yjkhan(a)gmail.com> wrote: > >> It's only a 15% difference in speed between PC2700 and PC3200. >> Sometimes you don't even notice a difference with a doubling of speed >> in some components, let alone 15%. >> >> You'll probably be able to demonstrate benchmarks which will prove it's >> faster, but you still won't notice it in your day-to-day use. There's >> two different measures of performance in most computer components: (1) >> bandwidth, and (2) latency. Bandwidth is akin to a topspeed, while >> latency is akin to an acceleration. In a car you feel its acceleration >> much more so than you feel its topspeed. Switching from PC2700 to 3200 >> is just an increase in topspeed, but not in acceleration. >> > >Very clear and very helpful! > >Thank you. > >Now here's my dilemma: ...my computer, (Celeron D 340, 533 MHz FSB), >came with one 512 MB PC2700 stick with 8 modules on it. I also have a >512 MB PC3200 stick with 16 modules on it. > >I want to run the system with a total of 1024 MB's, and I understand >that I should not mix x8 with x16 sticks, so I now need to puarchase >either a 512 MB (x8) PC2700, or a 512 MB (x16) PC3200. (Currently the >PC3200 is cheaper.) > >...so, does the 533 MHz FSB actually use the faster RAM (PC3200), or >does it top out with the PC2700??? I'm afraid this whole discussion has gone completely astray, partly due to lack of detailed info to start with. First the x8 and x16 you mention in HP specs elsewhere in the thread does not mean the number of chips on the DIMM - it's the width of the Data Out of the memory chips used. The HP specs you quoted are also talking about *dual* channel operation, which it was not clear your mbrd supported to start with... but apparently it does. Obviously with only one DIMM you are not running dual channel with only one DIMM inserted. For a 533MHz FSB, with a dual channel memory setup, the minimum speed match for memory modules is PC2100 (actually 8*266.6 = 2133.3). Two channels of those (4266.6) would match exactly your FSB of 533MHz (8*533.3 = 4266.6). HP, however has used PC2700 DIMMs, possibly because they are the most available. The bottom line is that the best peformance will be obtained with the dual channel setup and to get that you must have matched DIMMs, one (or two for larger memory capacity according to slots) on each channel. What does matched mean?... the same chip count, speed rating and chip arrangement on each pair of DIMMs across the two channels. Whether you could make it work with identically spec'd DIMMs from two different mfrs is a toss-up but I would not even try it myself. Your best bet: take a close look at the chips on the original DIMM and note the mfr name and see if you can find a similar DIMM from an online vendor, otherwise the only option is to cough up the HP price for a match. You could post the chip codes here and soemone will likely be able to decode them for you. Also, check out www.crucial.com and enter the details of your system to see what memory type and timings they recommend for it. -- Rgds, George Macdonald
From: dk_ on 5 Aug 2005 06:31 In article <19u4f1pivd4ofk0maim5cl6tm9j4q44n04(a)4ax.com>, George Macdonald <fammacd=!SPAM^nothanks(a)tellurian.com> wrote: OK. Here's where I'm at now... I opened the new machine again and I took out the single 512 MB stick and it is not a PC2700, but rather a PC3200, (i.e., 400 MHZ DDR, double sided with 16 chips). Today I purchased another 512 MB, 400 MHz DDR, double sided with 16 chips (a PC3200). HP says on the box that it was equipped with a PC2700, but you're right I'm sure, they actually used a PC3200 because of availability and cost. I installed both PC3200's and booted the computer and looked in the BIOS. The screen says there are two PC2700 sticks loaded, for a total of 1 gig total memory. The motherboard has a FSB of 533 MHz, and according to this thread, the motherboard will only use speed up to the PC 2100 (HP says PC2700). So why the heck is the BIOS showing #2 PC2700 sticks, when it should probably read #2 PC2100 sticks even though the machine actually is loaded with #2 PC3200 sticks???!@#$%^& BTW: where do these 4* or 8* multipliers come from? Regarding the discussion below about x8 and x16... you point out that these 2 numbers don't refer to the number of chips on a stick; I haven't see any FAQ's, or discussions, using those two numbers, so I assumed the numbers were referring to the obvious number of chips on a stick and that they should be the same # on each stick. The two sticks that are currently in the machine, are physically matched (at least). Q). How much of a difference would it make in performance if the two chips were actually identically matched as a set, as you recommend? (Currently by most criteria the two chips are matched, i.e., 512 MB, DDR 400, double-sided with #16 chips on each stick.) (I did notice that in the store, and on a RAM manufacture's site that they do talk about, and sell "dual DDR's" as a tested set. My motherboard is an 'MSI MS-6577 version 4.1' running a Celeron D 340 if that adds any useful information. -Dennis > I'm afraid this whole discussion has gone completely astray, partly due to > lack of detailed info to start with. > > First the x8 and x16 you mention in HP specs elsewhere in the thread does > not mean the number of chips on the DIMM - it's the width of the Data Out > of the memory chips used. > > The HP specs you quoted are also talking about *dual* channel operation, > which it was not clear your mbrd supported to start with... but apparently > it does. Obviously with only one DIMM you are not running dual channel > with only one DIMM inserted. > > For a 533MHz FSB, with a dual channel memory setup, the minimum speed match > for memory modules is PC2100 (actually 8*266.6 = 2133.3). Two channels of > those (4266.6) would match exactly your FSB of 533MHz (8*533.3 = 4266.6). > HP, however has used PC2700 DIMMs, possibly because they are the most > available. > > The bottom line is that the best peformance will be obtained with the dual > channel setup and to get that you must have matched DIMMs, one (or two for > larger memory capacity according to slots) on each channel. What does > matched mean?... the same chip count, speed rating and chip arrangement on > each pair of DIMMs across the two channels. Whether you could make it work > with identically spec'd DIMMs from two different mfrs is a toss-up but I > would not even try it myself. > > Your best bet: take a close look at the chips on the original DIMM and note > the mfr name and see if you can find a similar DIMM from an online vendor, > otherwise the only option is to cough up the HP price for a match. You > could post the chip codes here and soemone will likely be able to decode > them for you. > > Also, check out www.crucial.com and enter the details of your system to see > what memory type and timings they recommend for it. -- Dennis Kessler http://www.denniskessler.com/acupuncture
From: "dawg" <don't on 16 Aug 2005 19:53 No. Not unless you actually raise the FSB. PC3200 just means the ram is qualified to work UP TO 400(200) FSB. PC2700 is qualified to work UP TO 333(166) FSB. I believe your Celeron D works at a 133(133x4 for intel=533) FSB. AMD uses a different front side bus(x2) than intel which uses a x4 bus although they can both use the same memory.Weird huh? "dk_" <nobody(a)spamless.com> wrote in message news:nobody-DF2D91.02303703082005(a)corp-radius.supernews.com... > Will upgrading from a PC2700 512MB RAM stick, > to a PC3200 512 RAM stick make any noticable > difference in performance. > > My computer is running with a Celeron D 340, 533 MHz FSB. > > -Dennis > > -- > Dennis Kessler > http://www.denniskessler.com/acupuncture >
From: dannysdailys on 17 Aug 2005 07:32
As you can tell by all the posts, this is the problem with buying a manufacturers PC. They're simply a mix and matched mess of parts. Assuming the MSI is using an Intel chipset: As far as I'm aware, Intel doesn't even make a dual channel memory bus. That's Nvidias domain with the Nforce set of northbridge chips. So matching memory seems silly to me. Maybe I'm misinformed. Even at that, Nvidia's dual channel mode really only helps for on board video. It's less then a 3% increase without it. I found that out after I blew the money on a "matched" pair, put my computer in dual channel mode, and noticed NO speed improvement. Always remember, manufacturers are selling to the lowest common demoninator and say all kinds of things, if it will help avoid a tech support call. I'm sorry you threw out your old RAM chip, because it probably would have worked fine, even though it wasn't a direct match. You should have popped it in and see if the computer would boot. In a single channel environment, you can string any RAM modules together. The only caviet being: Your RAM bus will run only as fast as the slowest module installed. The only quirk I'm aware of doing this, is having to have the largest module in slot one. Otherwise, the system will only recognize what's in slot one, to two. Example: If you have a 128 in slot 1, and a 256 in slot 2; the system will only see 128 in slot 2. Maybe I'm missing something... |