Got a tip for us?
Let us know
Become a MacRumors Supporter for $50/year with no ads, ability to filter front page stories, and private forums.
333Mhz DDR?
- Thread starter arn
- Start date
- Sort by reaction score
Intel is still keeping RDRAM limping along, but have DDR options available across most of the chipset line.
Sort of a huge mistep on Intel's part, to design the P4 and chipsets for RDRAM and then continuously have it be beaten back by one bad press release after another.
All the while Rambus struggles to survive and avoid bankruptcy, while the lawyers continue to suck the Rambus dry over the patent spat.
I guess this attempt to corner the memory market could be called a dismal failure, but it's not over yet.
Sort of a huge mistep on Intel's part, to design the P4 and chipsets for RDRAM and then continuously have it be beaten back by one bad press release after another.
All the while Rambus struggles to survive and avoid bankruptcy, while the lawyers continue to suck the Rambus dry over the patent spat.
I guess this attempt to corner the memory market could be called a dismal failure, but it's not over yet.
Actually, it's "Swings and roundabouts"
RDram is high bandwidth, high latency, DDR ram is medium bandwidth, low latency, most of the time latency is more critical than bandwidth.
For most purposes IMHO, DDR ram (possibly in a 128bit/dual channel configuration like Nvidia's Nforce chipset) is a better solution that RDram
Intel are phasing out RDram by the way, Their new server chipset is DDR based, and they have no new Rambus chipsets on their roadmap.
DDR ram is 64bits wide
RDram is 16bit, but typically clocked a LOT higher (and it also uses DDR tech)
16bitx400Mhz DDR = 1.6GB/s = PC800 Rdram
64bitx100Mhz DDR = 1.6GB/s PC1600 DDR
Of course, RDram is typically dual channel (giving 3.2GB/s of bandwidth to a processor that can use it, which in the consumer market right now is basically the P4)
Yeah, every one knows about DDR on the new Macs... Whether it's 333 or 400 or even 266 will increase speed but I don't see that as being anything spectacular. DDR has been around for a while and finally moto has included support. What will be interesting is if Apple includes Serial ATA. If they do, they'll be the first major computer supplier that includes it and as I'm told, they'll have a 6 month jump on Dell and the like. Apple has been using ATA 66 (which is just as old as 133 SDRAM) for a long time.
I think I'm just wishful thinking because Seagate(?) just came out with the first retail serial ATA drive.
I think I'm just wishful thinking because Seagate(?) just came out with the first retail serial ATA drive.
Actually, with AMD's first DDR chipset you saw about a 10% increase (see www.anandtech.com) then with VIA's KT266A (133 Mhz-->266 DDR) you saw anywhere from a 10% to even as much as a 48% improvements over SDRAM. But with VIA's KT266 (original DDR solution, no A,) you saw little or no improvement with DDR. So it would appear that if done correctly DDR can give you at least a 10% improvement in scores, or if it's just a hack can have little or no effect.
Also, when you say AMD switch to 333 Mhz, the Front Side Bus is still at 133 (266 DDR,) only the memory is running at 166 (333.)
This is with VIA's chipset. We have yet to see synchronous FSB and memory at 333Mhz, without overclocking that is.
Originally posted by tjwett
DDR shmee-DR. yawn. BFD. the XServe doesn't even have true DDR support with it's fsb still at 133. for true DDR use you need the bus and the RAM. don't worry, Apple is still way behind
As always..... sigh
This is not exactly correct. Both DDR 266 and RDRAM 1066 have the same clock rate, 133Mhz. The difference between the two is what is going on during that clock rate. DDR accesses memory twice during the clock cycle (once up and once down, hence double data rate) while RDRAM accesses memory four times during the clock cycle (twice up and twice down, hence quad pumped). The 1066 comes because there are two channels (133 * 4 * 2 ~ 1066). Similarly the older RDRAM 800 had a 100Mhz clock rate (100 * 4 * 2 = 800).
Since the current G4s have a SDR 133Mhz FSB, there is questionable value to DDR 333 memory beyond the ooohhh factor. If the new G4s have a 166Mhz FSB then DDR 333 will be valuable if the memory controller is able to feed both processors or the FSB can do DDR like the AMD Athlons can.
I guess we will find out in a week or so.
RDRAM never did catch on in the server market. Early on the memory was too expensive and by the time the prices dropped, DDR RAM was nearly as fast and a safer bet. 1GB of RDRAM for a server would cost more than any other component in the system (unless you had a RAID array). Once Intel makes a good DDR 400 capable chipset and the supply is there, RDRAM will be about as common as EDO memory.
Um, no?
PC1066 is 16bits wide, 533Mhz Double Data rate, giving 2.1GB/s, but Rdram is typically deployed in a dual channel configuration giving 4.2GB/s total bandwidth (which lines up nicely with a Pentium 4B's 533Mhz - 4.2GB/s FSB)
The Pentium 4's frontside bus otoh, DOES run at 133Mhz x 4 transfers per clock
Someone knowledgable ?
Will someone with some smarts please answer said question that I've been asking for a while:
When the new Pmacs come w/ "DDR Ram" how will we know weather thats just DDR to chipset (like Xserve) or DDR to chipset to CPU, that yeilds the truely high performance ? what should I look for to determine the answer to this question?
Thanks
Will someone with some smarts please answer said question that I've been asking for a while:
When the new Pmacs come w/ "DDR Ram" how will we know weather thats just DDR to chipset (like Xserve) or DDR to chipset to CPU, that yeilds the truely high performance ? what should I look for to determine the answer to this question?
Thanks
Re: Someone knowledgable ?
There's got to be a downloadable utility somewhere to test this. It woldn't have to be really complicated and better yet it could be native unix.
Rocketman
There's got to be a downloadable utility somewhere to test this. It woldn't have to be really complicated and better yet it could be native unix.
Rocketman
Same here, It just seems like I'd have a lot more options if there we're more powerful macs to start with. 1Ghz or above with DDR on the entry level seem worth the wait to me. I've got no hope of buying a new mac this year but summer of next year wouldn't be a problem and by then who know's what we'll get for £1,300 or so.
Re: Re: Thanx
Dongmin, I agree. What Apple needs to do is get OS X running on IBM's PowerPC servers. Then they'll have an enterprise solution with relatively little investment compared to trying to keep up with the big boys in the server market, which they've proven they can't do.
Dongmin, I agree. What Apple needs to do is get OS X running on IBM's PowerPC servers. Then they'll have an enterprise solution with relatively little investment compared to trying to keep up with the big boys in the server market, which they've proven they can't do.
Re: Re: Re: Thanx
Or maybe for the high end server market, they should consider porting Max OS X to SPARC. Which would give it a full range of Sun systems to run on.
Or maybe for the high end server market, they should consider porting Max OS X to SPARC. Which would give it a full range of Sun systems to run on.
I don't know much about this, but wouldn't Apple need to up their system bus to 166MHz (necessitating a large motherboard remodeling) to use 333MHz DDR RAM? 333MHz would be nice, but I imagine we'll just see 266.
Bill
Bill
Apple needs a 166MHz bus anyway to compete with the likes of ASUS, Tyan, etc.
I hope they do. Come on, Daddy needs a new Tower!
Re: Re: Someone knowledgable ?
I dont think it's that easy.. plus, it'd be nicer if I knew what to look for on the motherboard, like if there were tell tale signs ? obviously there is a big performance boost, but I want to know if it's coming form a DDR to chipset to CPU bus thats wide open !!!??
I dont think it's that easy.. plus, it'd be nicer if I knew what to look for on the motherboard, like if there were tell tale signs ? obviously there is a big performance boost, but I want to know if it's coming form a DDR to chipset to CPU bus thats wide open !!!??
Actually not an indication of anything at Apple.
In addition to my Mac uses, I also build custom Windows systems. In the custom build and overclocking world, advertisement and use of ram beyond the official specs for a motherboard is common.
I hate to rain on everyone's parade, but this is just a vendor attempting to attract the kind of customer who either thinks that more is better even if the machine can't make use of it (there are a lot of these customers by the way) or the customer who wants to try to fiddle with the motherboard to make it run faster than rated.
For an example of this, consider two things:
1) There are currently no DDR based motherboards, Mac or Wintel (WinAMD) that support faster than PC 2700 (333 MHz DDR)
2) You can go to www.pricewatch.com right now and see dozens of vendors selling 366, 400, and even 433 MHz DDR memory (which you could also put in your XServe if you wanted, though it would only run at 266 MHz while installed there).
Is this because someone on the Windows side of the fence is going to put out a 433 MHz capable motherboard soon? No... Just because some people want to go overboard.
FYI about memory, you can put faster memory of the same type into your computer... It just won't run any faster than what your computer is rated for without some serious tweaks.
In addition to my Mac uses, I also build custom Windows systems. In the custom build and overclocking world, advertisement and use of ram beyond the official specs for a motherboard is common.
I hate to rain on everyone's parade, but this is just a vendor attempting to attract the kind of customer who either thinks that more is better even if the machine can't make use of it (there are a lot of these customers by the way) or the customer who wants to try to fiddle with the motherboard to make it run faster than rated.
For an example of this, consider two things:
1) There are currently no DDR based motherboards, Mac or Wintel (WinAMD) that support faster than PC 2700 (333 MHz DDR)
2) You can go to www.pricewatch.com right now and see dozens of vendors selling 366, 400, and even 433 MHz DDR memory (which you could also put in your XServe if you wanted, though it would only run at 266 MHz while installed there).
Is this because someone on the Windows side of the fence is going to put out a 433 MHz capable motherboard soon? No... Just because some people want to go overboard.
FYI about memory, you can put faster memory of the same type into your computer... It just won't run any faster than what your computer is rated for without some serious tweaks.
Originally posted by tjwett
DDR shmee-DR. yawn. BFD. the XServe doesn't even have true DDR support with it's fsb still at 133. for true DDR use you need the bus and the RAM. don't worry, Apple is still way behind
DDR--double data rate RAM uses the leading and trailing edges for transfer. So, its speed is double whatever the memory bus speed is. 133(.33) x 2 = 266(.66). 166(.66) x 2 = 333(.32) 200 x 2 = 400. That is true DDR.
