Servers - General
cancel
Showing results for 
Search instead for 
Did you mean: 

PA8x00 vs. Pentium?

 
SOLVED
Go to solution
W.C. Epperson
Trusted Contributor

PA8x00 vs. Pentium?

Can anyone post a link to a comparison of PA8x00 chip performance (hp-ux or Linux) vs. Pentium IV (Linux)?
"I have great faith in fools; self-confidence, my friends call it." --Poe
9 REPLIES 9
Leif Halvarsson_2
Honored Contributor

Re: PA8x00 vs. Pentium?

Hi
Perhaps you can find something here, check CPU2000 or CPU95 benchmarks.
Paula J Frazer-Campbell
Honored Contributor

Re: PA8x00 vs. Pentium?

HI

Not a link but:-

A RISC processor (reduced instruction set) of the same speed at an Pentium IV will process faster because for each call to the processor it steps through until it find which instruction it requires.

Stepping through a PA-RISC machines which uses an instruction set that is based on 32 general-purpose registers, compared to a pentium with I believe 55 registers will be slower. These step throughs happen millions of time a second and all add up to the Pentium chip being slower.



I also found this on the Intel site? Nice to know isnt it.

The Pentium processor may contain design defects or errors known as errata which may cause the product to deviate from published specifications.


Paula
If you can spell SysAdmin then you is one - anon
Pete Randall
Outstanding Contributor

Re: PA8x00 vs. Pentium?

W.C.,

There's an extensive research report here:

http://www.dl.ac.uk/CFS/benchmarks/compchem.html


Pete


Pete
Pete Randall
Outstanding Contributor

Re: PA8x00 vs. Pentium?

W.C.,

And here's a SPECmark table:

http://www.immt.pwr.wroc.pl/faq/msg00156.html


Pete


Pete
Bill Hassell
Honored Contributor
Solution

Re: PA8x00 vs. Pentium?

You're trying to compare apples to alligators. A RISC machine has just a few dozen unique instructions while CISC (like a Pentium) has hundreds of instructions which translates into highly variable instruction completion time. RISC is quite easy to provide pipelined instruction execution which means that 3 or 4 (or more) instructions are being executed at the same time. Now this isn't parallel execution (they don't start at the same time) but overlapped execution. One instruction is being fetched, a previous instruction is obtaining register data, and another is performing aritmetic tasks and another is storing the results, etc. This means that optimization and getting more than one instruction to run per clock cycle is fairly easy.

On the other hand, large instruction and data caches and similar overlapping instruction techniques in Pentium chips can narrow the differences. One thing that is quite difficult to do is to compare clock speeds directly. You will usually find (in compute-bound programs) that RISC accomplishes more per clock cycle, and that the equivalent CISC chip will need a faster clock speed to match a given RISC clock speed.

But all of this is smoke and mirrors until you define what the real load will be. PC-based processors suffer from tremendous legacy designs for I/O and it is much harder to find boxes that can handle massive I/O. On the other hand, most RISC machines require proprietary I/O cards. So until you define the goal: arithmetic (ie, floating point) processing, database processing (disk and memory) or web services, etc, it will be difficult to compare the hardware performance.


Bill Hassell, sysadmin
Patrick Wallek
Honored Contributor

Re: PA8x00 vs. Pentium?

Nothing contstructive to add, but I laughed when I read the first line of Bill Hassels response. "...trying to compare apples to alligators." I love it.

No points please!!!
John Flanagan
Regular Advisor

Re: PA8x00 vs. Pentium?

I can only tell you what I have. A HP D270 and a Dell 1GHz XEON (Win 2K). The dell is about 4 times faster (on an oracle query) and cost about 1/3 of the price but it was bought about 18 months later.

There is no easy answer!

John.
W.C. Epperson
Trusted Contributor

Re: PA8x00 vs. Pentium?

Bill,

I've respected your knowledge and intelligence for a lot of years, so I'm a little confused by your ridiculing the question as asking for an invalid comparison, then proceeding to give a well thought out, concise answer comparing the performance characteristics of the architectures.

And the response to the implicit question of which sort of load I'm interested in is "Yes": I run PA-RISC boxen for each of those characterized applications, and am interested in relative performance in each area. Further remarks or links will be welcomed.

regards,
j.

"I have great faith in fools; self-confidence, my friends call it." --Poe
Ted Buis
Honored Contributor

Re: PA8x00 vs. Pentium?

I think Bill is just trying to say that the question is very hard to answer if you don't focus on a specific application area. There is nothing wrong with the question as many people want to know what is the right "tool for the job". Without more specifics on the "job", you have to may some assumptions or start listing some or all possible jobs. HP-UX scales to much larger number of processors on PA-RISC than LINUX on Pentium, so there are some applications where PA-RISC will scale well beyond what is possible with LINUX. You don't see much on LINUX in the TPC-C area. If I am running a client side JAVA application, which is 32-bit, I am likely better off with a Pentium IV due to the higher clock rate. You can always go to www.specbench.org and www.tpc.org and start comparing the benchmarks, but be prepared to see different results for different jobs.
Mom 6