Intel's 925X & LGA-775: Are Prescott 3.6 and PCI Express Graphics any Faster?
by Anand Lal Shimpi on June 21, 2004 12:05 PM EST- Posted in
- CPUs
It's been such a long time since we've had as exciting a product as Intel's 925X platform arrive in our labs. The platform brings about a new CPU interface (LGA-775), a new graphics interface (PCI Express x16), a new memory interface (DDR2) and a slew of other tweaks that make for an impressive bundle of technology. Unfortunately for Intel, we are much more than just technologists - we are pragmatic technologists.
We have already shown how Intel's 925X and 915 platforms basically offer no performance increase over current generation 875P/865 platforms. The lack of performance improvement can essentially be attributed to the high latency of current DDR2 memory, combined with the lack of bandwidth utilization of DDR2-533. These two problems can and will be addressed in the future by lower latency DDR2 memory as well as Prescott's forthcoming 1066MHz FSB (which will be very well matched to a DDR2-533 memory bus). Once again, unfortunately for Intel, we are talking about present day performance and the situation isn't as perfect as it would be had we been given both of those things.
So, the launch of the 925X and 915 has come and gone, with very little excitement from the community in regards to platform performance - but are there any other diamonds in the rough to be discovered?
Alongside the LGA-775 socket interface, Intel gave Prescott a bit of a speed bump - taking it up to 3.6GHz, making it the highest clocked Intel processor available today. This article will be taking a look at the extra 200MHz and how it changes, if at all, the Prescott factor.
Then, we have this issue of PCI Express graphics; Intel has pretty much guaranteed a fast transition to PCI Express graphics cards by removing any AGP support from their 925X/915 chipsets. Intel is expecting that half of all Intel platforms will be 9xx based by the end of 2004, meaning that 50% of all of Intel's platforms shipped by the end of 2004 will not have AGP support. Like it or not, PCI Express as a graphics bus is here.
But what about performance? Both ATI and NVIDIA have been duking it out over the past several months about whose PCI Express solution is the best. And now, we're finally able to find out. Toning down the suspense a bit, you'll find that the whole PCI Express debate was really much ado about nothing, but we'll have some more explanation and benchmarks showing that in the coming pages.
With the above paragraphs, we've pretty much summed up what you can expect out of this article, but wait, there's more (cue TV salesman). This week, we will also take an in-depth look at one other feature offered by the platform and investigate the real world performance benefits of Native Command Queuing. NCQ is supported in the new ICH6 South Bridge and is claimed to improve performance significantly; we'll see what that means in the real world soon enough.
With that said and done, let's get to it.
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Pete - Monday, June 21, 2004 - link
*Sweet.I'm thinking those 6800U benches are probably input errors on AT's part, as most other sites show:
1) scores nowhere near that high, especially at that res, &
2) A64s outperforming P4s.
You may be using a very GPU-limited, or at least not-CPU-limited demo, though.
Pete - Monday, June 21, 2004 - link
Swet, fancy Moses! Anand, can you explain the ginormous "vanilla" Far Cry gains by the 6800U? Was IQ the same as the 61.11s (still "point-filtery" in some places compared to ATi) with such prodigious (70%!) gains?justly - Monday, June 21, 2004 - link
AnandI don’t care if that info is strait from Intel or not, it is plain wrong, and I think you are wrong for not questioning this and more so by putting it in print.
Conduction is increased with pressure (be it heat or electrical) but for downward force to affect electrical contact/conduction of a CPU in a socket the pins would have to make contact at their tip. A ZIF socket does not do this, it makes contact on the side of the pins when a sliding plate forces the pin against a contact. If contact was made at the tip of the pins then the CPU would not lay flat against the top of the socket when inserted. This would also prevent aftermarket adapters like this one from powerleap http://www.powerleap.com/PL-iP4.html from being used between the CPU and the socket because it would prevent the pins from contacting.
Once the CPU is inserted into the socket and the lever is locked down the CPU is locked flat against the socket so even if downward pressure was applied it would only help with heat transfer.
Runamile - Monday, June 21, 2004 - link
I agree with #4. The ZIF socket takes care of all contact needed. And as #15 said, there is a sideways force that makes contact with the pins. Ever seen that Tom's Hardware video with the PIII and P4 running w/o a heatsink, albeit very slowly due to freak overheating? They did 'need' the extreame downwards force. Thats all for heat transfer. Period.All in all, very enlightening article. Basicly shows that the entire 925X/LGA-775/Prescott/DDR2/PCI-X release is a mediocre waste of our money. At least for the time being.
paulvds - Monday, June 21, 2004 - link
478 pin electrical contact is by a pinchingsideway force on the pins produced by the ZIF
lever, top down force is totaly irrelevant!
How could you gobble-up that marketing nonsense ?
You advise 'business users' to chose AMD...
Also total nonsense, any entry level value processor will do, they don't need teraMips...
You should go write poetry or novells...
danidentity - Monday, June 21, 2004 - link
Great article Anand...Do you have any info on the supposed Intel-imposed 10% overclocking limit described in Tom's Hardware Guide's LGA775 article here?
http://www.tomshardware.com/motherboard/20040619/s...
retrospooty - Monday, June 21, 2004 - link
Nice article...It just basically proves what we have all suspected all along. DDR2, PCI express, and socket 775 dont offer any compelling reason to upgrade (for now anyhow).
Of course in the future (maybe 2005 if we're lucky), when graphics cards can utilize the extra bandwidth of PCI express it will be faster than AGP 8x.
Of course in the future (maybe 2005 if we're lucky), when DDR2 800 mhz is standard, it will be faster than low latency DDR400
Of course in the future (even if hell freezes over) the message is clear socket 775 has failed :D
LOL !
T8000 - Monday, June 21, 2004 - link
I think the pins in the LGA775 socket are a lot longer then the CPU needs.So adding some kind of non conductive shim around the pins could make this socket a lot more reliable.
It could be as simple as a thin plastic plate with 775 holes in it, that could be inserted before the CPU, leaving just enough pin length to mount the CPU, without the risk of bending those pins.
Anand Lal Shimpi - Monday, June 21, 2004 - link
phobsThanks for the heads up, we added the last two pages of benchmarks after the fact and I forgot to remove that line :)
Take care,
Anand
Anand Lal Shimpi - Monday, June 21, 2004 - link
justlyThat information is straight from Intel - the force of the heatsink was used to maximize heat transfer, but not that much force is necessary to maximize heat transfer. The rest of the force is needed to ensure that there is good contact between the pins and their contacts.
Take care,
Anand