Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Path: utzoo!decvax!decwrl!pyramid!hplabs!oliveb!intelca!clif From: clif@intelca.UUCP Newsgroups: net.micro.ns32k Subject: Re: Re: National's 32332 (Apples and oranges really) Message-ID: <88@intelca.UUCP> Date: Wed, 11-Jun-86 14:17:13 EDT Article-I.D.: intelca.88 Posted: Wed Jun 11 14:17:13 1986 Date-Received: Wed, 11-Jun-86 23:52:51 EDT References: <746@usl.UUCP> <253@spar.UUCP> <2793@sdcrdcf.UUCP> <1768@gitpyr.UUCP> <2020@hammer.UUCP> <216@motsj1.UUCP> <3522@uk <930@alberta11 Jun 86 18:17:13 GMT Distribution: na Organization: Intel, Santa Clara, Ca. Lines: 90 > > Far be it from me to call Mr. Purkiser biased B-). > But let's get it straight that the PC/AT benchmark being > referred to is "SMALL MODEL" and (correct me if I'm wrong) > 16 bit ints. Contrast that to 32 bit addresses and ints > in the Balance. > I was kidding about myself being unbaised, hence the :-) symbol. Yes the PC-AT Dhrystone numbers I quoted where small model, last I looked the Dhrystone fit easily in 64K of code and data. > A long list of Dhyrstone numbers was deleted here along > with some comments about the "unfortunate" popularity of PC AT > machines (quotes from my orginal article in >> ) > > In order for the 15 MHz 32332 to be faster than an 68020 (much less > > a 386) it would have be 3x faster than an 10MHz 32032. The increased > > clock frequency accounts for 1.5x, I am hard pressed to imagine where > > the other 2x could come from. > > I may find that hard to imagine. But why would you? > If we are to believe the Dhrystone figures posted to the net, > your company did just that in going from the 8086 to the 80286, ie. > obtained a 2x speedup for the same clock frequencies. > > > This is just the observations of a disinterested :-) person. > > You may be disinterested, but I am not. I'm tempted to resort > to personal insults here, as the amount of resources that have > been/will be spent on x86 systems does not bear thinking (or > smiling) about, but of course I'll refrain. > > Bjorn R. Bjornsson > Department of Computing Science > University of Alberta > Edmonton > > ihnp4!alberta!bjorn My point was not that PC-ATs and 286 are faster than 32032. This point (really 16-bits vs 32-bits) has being debated for some time on the network and I doubt that there is anything more either one of us could add to the discussion. Rather my point was what significant architectural improvements were made to the 32332 to give it a 2x performance boost at the same clock frequency? After reading the data sheet and other information on the part I am only aware of a few improvements made to the 32332 vs 32032. 1. Burst Mode Bus, useful for cache systems and possibly DMA-like transfers 2. 32 address lines, no performance increase 3. large prefetch unit, some performance boost. How could these architectural improvements double the performance? It is certainly possible that I may have overlooked some important things since I can no longer find my 32332 literature. However in my opinion the main improvement that the 32332 has over the 32032 is clock speed. The clock speed boost alone would not make it faster than a 68020. In contrast, there were many architectural improvements in the 86 vs the 286. Additional commonly used instructions e.g. push immediate, faster multiply etc. The most important 8086 to 286 improvement was the addition of special purpose hardware to calculate the effective address. Effective address calculation which took 6-12 clocks on an 8086 take only 1 clock on the 286. This resulted in an almost 2/3 reduction in average clocks/instruction between an 8086 and 286. This is responsible for the 2.5-3x performance advantage at the same clock frequency. The major architecture improvement of the 386 compared to the 286 is going from 16-bits to 32-bits. The other improvements, orthogonal registers, the addition of scaled-index addressing, and the shaving of 1 clock of the execution of most common instructions, while important, are not as dramatic as the 8086 to 80286 performance improvements. I standby my statement that I do not believe that an 15MHz 32332 is faster than a 16.7 MHz 68020 (much less a 80386). If somebody actually gets 4000+ Dhrystones from a 32332 I would be surpised. While I do not believe that Dhrystones are a perfect measurement of performance, I think they are pretty darn good. -- Clif Purkiser, Intel, Santa Clara, Ca. {pur-ee,hplabs,amd,scgvaxd,dual,idi,omsvax}!intelca!clif {Stamp Out Stupid Signatures}