• Welcome to Overclockers Forums! Join us to reply in threads, receive reduced ads, and to customize your site experience!

RAMBUS--aka--RD-RAM vs. DDR-SDRAM

Overclockers is supported by our readers. When you click a link to make a purchase, we may earn a commission. Learn More.

BLitzKrieG0187

New Member
Joined
Oct 13, 2001
Location
Ohio
RAM is very impt. in computing, and always has been. Over the past week I have been comparing the new DDR-SD 2700 RAM with PC800 RD-RAM. This is what i have discovered. First off, lets look at the specs. in comparison: So far, there are three types of DDR-SD RAM for your comp, one that was specifically used in utilizing the AMD 200MHz FSB. The newer types, PC2100 and PC2700 utilize AMD's newer FSB speeds. The newest PC2700 DDR-SDRAM has a delivery bandwidth of 2,666Mbs........ roughly 2.7Gbs, hence the name PC2700. Anyway, this RAM delivers at 333Mhz, it is also called DDR-333 RAM. So let's break it down, 333Mhz/~2.7Gbs per sec. This is the most advanced DDR-SDRAM is on the market right now for your comp. Now, let's have a look at what RD-RAM, or RAMBUS, has to offer in terms of power and so forth. RAMBUS has three new common forms, PC600, PC700, and PC800. Looking at the newest RD-RAM, PC800, it utilizes P4's 400MHz FSB speed, and has a delivery bandwidth of 3.2Gbs per sec. RD-RAM utilizes a dual-channel delivery system,which, in turn, delivers the RAMBUS at a finalized set speed of 800Mhz, hence the name PC800 RD-RAM. Broken down, this is expressed as 800MHz/3.2Gbs per sec. Even if DDR-SD RAM was running at 400MHz, that would still be only half the speed, or only utilizing one channel, that RD-RAM can offer as well as support. In terms of bandwidth on the RAM, RD-RAM still has over a 1/2 Gigabyte lead in delivery per second. Now, I am not saying that DDR-RAM isn't good enough, or is inferrior. I am just saying that I definitely don't think that DDR-RAM is all that it is coughed up to be for actual "system memory". I think that it is great that it is being offered in video card memory, but I wouldn't feel safe saying that it has such a great future ahead in the "system memory" category. I say this for two reasons; right now the technology and raw power in this RAM is still a whole step behind RD-RAM in terms of speed and performance/delivery. Secondly, and most importantly, it may be too late of an introduction for it in the "system memory" category, and if you don't think so, then u probably need to retract your statement that you just thought about in your head while reading this. I mean, lets face it, EDO ram is obsolete, SD-RAM's of all types including PC133 RAM are obsolete, and frankly, you can only push synchronus-dynamic ram so far before it maxes out, or becomes just "Hype". I have seen the benchmarks using this kind of RAM in AMD's of all architectures, and seen it against powerful P4 processors with PC800 RD-RAM. The DDR RAM in the benchmarks still pales in comparison to RD-RAM, in every aspect. And your thinking, yeah right, DDR RAM will win in the long run, or is already winning the "RAM BATTLE". Well, look at at this way, AMD's architecture is in just about every way, superrior to the P4's arch. Intel has to resort to using high clock frequencies just to barely beat out the newest AMD on the block when it comes to benchmarks. So this is what I have come down to............... the only way for DDR-RAM to succed is if it gains major popularity with it's new "tester", Intel. If it succeeds, then you might possibly see it in the P5 when it comes out. If it doesn't hit it off with Intel, then it pretty much will have no future or hope of finding it's way into future PC's around the globe. Remember this, when benchmarking, your pretty much looking at the architecture of the platforms processor, not really so much the architecture or power of the RAM. Intel might be able to make DDR-RAM a big hit, but, if it flops for their architecture of their processor, which I am certain that it will, it won't even be a worthy technology any more. Double Data Rate vs. Dual Channel RAMBUS DYNAMIC............... I like this already. Just remember kiddies, DDR RAM is still JUST "SD-RAM"............ LOL ! Some people tend to forget that... it is a pasttime technological advancement, no matter how much it is tweaked and repackaged. For those of you guys that are interested in RD-RAM aka RAMBUS, I reccomend going with the current PC800 RD-RAM w/ECC, for the extra buck, you won't regret it. Why go with just a high-end RAM when you can go with a State-of-the-Art RAM. Props to the 10 years of development that made RD-RAM so great. Oh yeah, just remember what I am comparing in this msg, RAM types, not which cpu is better in the benchmarks....... if AMD would cough up the money as well as the majority of true "Gamers", then they, as well as these gamers, would really see just how far AMD proceesors will go by supporting this superrior technology........... in the benchmarks, as well as with it's overall quality. Without RD-RAM, Intel p4's would suck even more. If AMD processors would go the extra mile and start supporting PC800 RAMBUS, and future higher speed RAMBUS's, then AMD would be that much better, widening the performance gap between both rivals. That's why I went with a P4 1.5Ghz, with Dual-Channel RAMBUS of 512mbs. I may not have the best processor on the market right now, but I certainly got it right where it counts: an RD-RAM board instead of a DDR-SDRAM board. I have four 128mb RD-RAM mods installed. I like to call it my Quad channel, or quad stream delivery system. Also, RD-RAM can be mixed and matched with different speeds and different mfgs., and it will still run 100% smoothly. How many RAM technology's out there can make that claim, try none. Consider yourselve's educated by an educator.

"Don't hate the playa, hate the game."

|3Li+z|<rieG
 

UnseenMenace

UnseenModerator
Joined
Apr 23, 2001
I am fully aware that Double Data Rate SDRAM is little more than a small evolution of current SDRAM technology. DDR SDRAM is capable, like RDRAM, of transferring data on both the rising and falling edges of the clock cycle. As such, its effective bandwidth is doubled. Consider standard 100 MHz DDR SDRAM:
(100 MHz Operating Speed) x (2x Rising & Falling) x (64-bit Bus) / (8 bits per byte) = 1600 MB/s available bandwidth.
As the numbers illustrate, DDR SDRAM, in conjunction with a 100 MHz FSB can provide bandwidth equivalent to that of RDRAM. Of course, like standard SDRAM, DDR SDRAM can be made to operate at a 133 MHz FSB as well.
(133 MHz Operating Speed) x (2x Rising & Falling) x (64-bit Bus) / (8 bits per byte) = 2133 MB/s available bandwidth.
When utilized with a 133 MHz FSB, DDR SDRAM can provide greater bandwidth than RDRAM. Thus, DDR SDRAM is able to achieve equal, or even higher, bandwidth levels while maintaining SDRAM’s lower latency.

Technology has become cost effective thus in my opinion making an upgrade path not a point of concern with most systems now just being replaced, not to mention by the time that the mass market choose to do this advances will be made in RAM technology which means that newer and faster types of RAM wil be available such as QDR (Quadruple Data Rate) and as such the future for both DDR and RAMBUS will be short.. It may aslo be worth pointing out at this time that Intel has put considerable resources in attempting to stop via release a DDR based P4 chipset which is known to be the most cost effective/performance option available at this time, which matters to a lot of people.. If RAMBUS was such an advance over DDR why then are intel so bothered about a chipset which has the posibility of increasing sales of their products?... Could it be due to the fact that the huge performance difference of RAMBUS is a myth in the same manner that Intel proved how good the P4 was at MPEG encoding by using a modified and enhanced codec which was unavailable to the general consumer?
RAMBUS is not a cost effective performance solution which is being shown by the release of SDRAM Pentium 4 mobo's and by the time it can become cost effective the industry will have moved on.
You state that RAMBUS can be mixed with different speeds and manufacturers but I also do this with DDR however I can choose to run 1 stick of RAM or 3 if i choose to do so, unlike RAMBUS which has to be installed in pairs.
lets face it the educated among us know that Pentium 4 is a strangled product, it is not a great value for money product or a great performing setup without having software specifically written for it, the socket design is changing once again and by the time any noticable improvements come from this design, the industry would have moved on and so would we.

NOTE :- Benchmarks can be faked, they can created be in situations using software which places a specific product in a good light, they should be taken with a pinch of salt imho
 
Last edited:

Big Mike

Senior Head of Import Performance
Joined
Dec 17, 2000
Location
Fort Wayne, IN
While DDR-ram can't keep up with the bandwidth and in cheesey synthetic tests like Sandra's memory test ( i like sandra as much as the next guy but it doesnt always tell the whole story ) it stomps it, it quite often gets left behind in "real world" type benchmarks...and that is quite simply because of its poor latency qualities, if your rapidly moving around in the banks of the ram RDRAM loses any edge it had during its latency cycles before it blasts the info through its massive pipeline. Neither type of ram at this point is the ultimate and final solution but as far as im concerned when choosing two soon to be obsoletes that dont have a huge discrepency in performance in the real world ill take the cheap one (DDR) I'm not trying to start a flame war but I think that looking at only the bandwidth only shows part of the picture. Also RDRAM is worthless with a cpu that isnt optimized for it like the P4 is. Rambus only sells its product because all those lines of blacked out text in their contract with intel basically makes intel their slaves. RDRAM on an athlon machine for example would be nothing but a waste of money. Also Nvidias dual channeled DDR chipset should significantly level the bandwidth playing field.