Intel's Pentium 4 E: Prescott Arrives with Luggage
by Anand Lal Shimpi & Derek Wilson on February 1, 2004 3:06 PM EST- Posted in
- CPUs
Execution Core Improvements
Intel lengthened the pipeline on Prescott but they did not give the CPU any new execution units; so basically the chip can run faster to crunch more data, but at the same speeds there are no enhancements to work any faster.
Despite the lack of any new execution units (this is nothing to complain about, remember the Athlon 64 has the same number of execution units as the Athlon XP), Intel did make two very important changes to the Prescott core that were made possible because of the move to 90nm.
Both of these changes can positively impact integer multiply operations; with one being a bit more positive than the other. Let us explain:
The Pentium 4 has three Arithmetic and Logic Units (ALUs) that handle integer code (code that operates on integer values - the vast majority of code you run on your PC). Two of these ALUs can crank out operations twice every clock cycle, and thus Intel marketing calls them "double pumped" and says that they operate at twice the CPU's clock speed. These ALUs are used for simple instructions that are easily executed within 1/2 of a clock cycle, this helps the Pentium 4 reach very high clock speeds (the doing less work per cycle principle).
More complicated instructions are sent to a separate ALU that runs at the core frequency, so that instead of complex instructions slowing down the entire CPU, the Pentium 4 can run at its high clock speeds without being bogged down by these complex instructions.
Before Prescott, one type of operation that would run on the slow ALU was a shift/rotate. One place where shifts are used is when multiplying by 2; if you want to multiply a number in binary by 2 you can simply shift the bits of the number to the left by 1 bit - the resulting value is the original number multiplied by 2.
In Prescott, a shift/rotate block has been added to one of the fast ALUs so that simple shifts/rotates may execute quickly.
The next improvement comes with actual integer multiplies; before Prescott, all integer multiplies were actually done on the floating point multiply unit and then sent back to the ALUs. Intel finally included a dedicated integer multiplier in Prescott, thanks to the ability to cram more 90nm transistors into a die size smaller than before. The inclusion of a dedicated integer multiplier is the cause of Prescott's "reduced integer multiply" claim.
Integer multiplies are quite common in all types of code, especially where array traversal is involved.
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Chadder007 - Monday, February 2, 2004 - link
I can't imagine how HOT that sucker will be when up to 5ghz!!!! 150oC??? LOLFor the heat issues alone, im thinking about going AMD in my next rig.
CRAMITPAL - Monday, February 2, 2004 - link
Ace's Hardware summed it up well: Prescott is a DOG, or to be exact a HOT DOG ! See the picture in the review of the dog warming it's toes next to the Prescott powered PC. Talk about one sad CPU piece of crap...Here is the FLAME THROWER reality check:
"Currently there is no reason to upgrade to Prescott, as the gaming performance is more or less ok, but many applications report pretty poor results. On top of that, the new Intel CPU gets hot very quickly and requires a well ventilated case. The Athlon 64 3200+ is not always the clear winner in games compared to 3.2 GHz Prescott, but the 3400+ will have little trouble beating the 3.4 GHz Prescott in most benchmarks. Prescott will have to scale incredibly quickly to outperform the Athlon 64, because the latter scales excellently with clockspeed, and we definitely prefer Cool'n'Quiet over Hot'n Prescott! "
As shown this FLAME THROWER don't scale well, especially when it runs 15-20C hotter than an equal speed Northwood. Intel really fugged up this time. Ya gotta love seeing the Satan eat shit and choke! When every hardware review site on the planet, including THG's tells ya Prescott is a piece of crap, then you might as well resign to reality. DENIAL is futile!
Dell will be selling FLAME THROWING PC Heaters to any gullible sheep foolish enough to buy a Prescott. A fool and his money are soon parted !
AnonymouseUser - Monday, February 2, 2004 - link
"Ummmm yea, kinda reminds me of cooking an egg on an Athlon XP"Yeah, kinda, except the Prescott can do the same work in about half the time. Sounds like something they should advertise that as a feature...
Stlr22 - Monday, February 2, 2004 - link
What happened to CRAM's post???INTC - Monday, February 2, 2004 - link
#43 cliffa3 - http://www.x86-secret.com/articles/cpu/prescott/p4...It doesn't look good for P4G8X with either the 2.8/533 or the 800 MHz FSB flavors.
mkruer - Monday, February 2, 2004 - link
For those who missed it, X-bit gave a temperature comparison, for the all the chip.http://www.xbitlabs.com/articles/cpu/display/presc...
Processor; Idle, Burn
Pentium 4 (Prescott) 3.2GHz; 45oC, 61oC
Pentium 4 (Northwood) 3.2GHz; 30oC, 48oC
Pentium 4 Extreme Edition 3.2GHz; 32oC, 51oC
This does not bode well for Intel unless they are going to make water cooling a standard.
But this Quote sums it up nicely IMHO “I am scared to imagine what happens to Prescott when we close the system case…”
lmonds - Monday, February 2, 2004 - link
what??? no talk about heat on this chip? Come on anand this is vital info about prescott. Other sites are reporting temps up around 80c with the stock cooler. I understand that as it gets faster in mhz it will be a better performing chip but what kinda heat are we looking at at 4ghz? No way is a 80c chip going in any of my boxes. If keeping an intel badge on the front of my case means i have to have a delta fan in my box then you can forget about it.Stlr22 - Monday, February 2, 2004 - link
:DCaptante - Monday, February 2, 2004 - link
Stlr22 ....Re post # 31 Hahahahahahahahahahahahahahahahahahahahahaaha!!!!That one had me cracking up for 5 minutes!
It is good to laugh!!! :-)
Stlr22 - Monday, February 2, 2004 - link
Moreless a Prescott....