Bottlenecks

[dakels]

Of course computer technology will always produce a newer better whatever every few weeks but in our current home systems, where is the real bottleneck for the most common aggressive tasks? Like decoding DVD or audio, or rendering 3D, gaming, etc.

What made me think about this is reading up on the new 800mhz FSB speeds. From the test results, there didnt seem to be a huge improvement (3-10% in most specifically targeted benchmarks). It seems to me the CPU cannot saturate the bus to really justify the 800mhz leap. I understand that it's a nice fat pipe for future, faster systems but for now, it seems like overkill. On a decently setup home system say P4 3.05 HT, 512mb DDR 2700, 7200 rpm hard drive, decent vid card, etc, running the above stated function, where is the main bottleneck? What part of that chain is the weakest link and would affect overall performance the greatest if the technology itself was greatly improved? What technology looks to be the biggest performance effect on home computers? what about something like IBM's multicore multithreading processor?

I understand if alot of this could be grey areas. I'd just like to hear some thoughts and opinions on the state of current technology and near future advancements.

 

[AndyHui]

Hard drive is by far the slowest item.

 

[Haden]

For DVD ripping/encoding DVD reader would be slowest part then cpu,
for rendering given you aren't using huge textures - cpu would be your bottleneck. Lots of particles and raytracing kills any modern cpu (thought I'm no expert here).

 

[AbsolutDealage]

Originally posted by: AndyHui
Hard drive is by far the slowest item.

Indeed. In fact, it is around 10^6 times slower than your average RAM.

 

[dakels]

I understand that the HD may be the slowest item (other then removable media) but how much of a globa difference on average, would it make if it were significantly improved? Say I put in a 15,000 rpm Serial ATA drive, would that be much better then going from a 2.4ghz processor to a 3.06 HT?, or going to dual channel DDR, or 800 FSB?

I know certain tasks are obviously more dependant on certain parts more then othres, such as rendering 3D is very CPU and RAM intensive, and Audio is very CPU intensive, working in a 1 gig DVD file maybe more slowed by the HD, or you biggest gaming delays may be the load time which is mainly HD. I understand how varied in can be per task, but I am speaking global average if you could say that. For instance a PC Mark benchmark which is a poor way to guage your specific needs, but decent overall computer average performance check?

Are you guys saying the HD is the weakest link and that an increase in faster HD technology would be the best overall global performance booster? Especially considering how Windows loves its VM. What about the ATA bus? I know thats not easily saturated by current ATA133 hard drives so I can't imagine that bottlenecks too much. How much faster real world is serial ATA? Does it saturate the bus often or come closer on average then ATA?

 

[Shalmanese]

It all depends on what you are doing. There is no realy one bottleneck to the system.

For most computing tasks, the bottle neck is that ~80kg sack of squishy water banging on the keyboard.

 

[dakels]

I am 79kg Shalmanese...

I have been rethinking my question and I agree. Its the applications/specified tasks that create the demands on our hardware so without stating to which tasks, its hard to really say where the bottlenecks are and you are right, most of the time it is the person. The only times I see any significant delays in my personal workload is with audio/video work and most of that bottleneck comes from the CPU itself. Then of course there are some games but thats hard drive since the only times I lag is map load times.

 

[Slammy1]

LOL. I know I probably shouldn't be posting here. I'm a computer junk man, as I'm sure a lot of hobbyists are. I go on the upgrade strategy that you look for bottlenecks, and that's what you upgrade. If you find your load times are unacceptably long, you need a faster drive; that sort of thing. Eventually, you have to chuck a major chunk of components, but it's a nice transition between technology advances. In the end, I see quality components intelligently upgraded as the key to stability and an effective computer. It gets built around how you use it that way.

 

[PrinceXizor]

This is an interesting topic and one I've commented on before when discussing the recently released WD Raptor. In most benches, the WD was SIGNIFICANTLY faster than other IDE drives (i.e. >30% sometimes 100% or more). AT's testing methodology utilized sequential I/O ops based on standard office suite benches such as Content Creation and the like.

Now almost EVERYONE agrees that the HD and related I/O system is the biggest bottleneck on today's PC's...yet when a HD comes out with significantly faster write time, access time, transfer rate, etc...those 'standard' benchmarks increase by 1-3% at most, i.e. negligible.

So how come when the perported bottleneck of the I/O subsystem is bulls-eyed by something (in this case the Raptor), why did related benches generate barely a ripple?

Are the benches formulated improperly?
Are they really assessing something different than we normally assume?
Is the I/O subsystem really the biggest bottleneck in a computer?
If so, is perhaps the HD NOT the issue, but something else we take for granted that could be improved?

P-X

 

[Shalmanese]

Because typical usage patterns act something like: Stress HD 100% for 5 seconds, Stress Memory 100% for 10 secs, Stress CPU 100% for 3 secs, Stress HD %100 for 15 secs. So you never really get a 100% performance out of anything. You have a a series of different bottlenecks.

 

[passign]

You have a a series of different bottlenecks.

interesting, this made me think.

but there's always only 1 neck.

or they'd call it infinite tilda

 

[Buddha Bart]

don't forget bandwidth!

even on fat pipes

bart

 

[LuckyTaxi]

Originally posted by: AbsolutDealage

Originally posted by: AndyHui
Hard drive is by far the slowest item.

Indeed. In fact, it is around 10^6 times slower than your average RAM.

did not know this

 

[sao123]

The real problem is both the OS and software.
There is no OS/Software which takes full advantage of the hardware capability we have.
Hint: Most of the computers time is spent in waiting.

No particular piece of software can feed the CPU & Memory subsystem, enough data & instructions to keep it busy for long enough, (except for maybe SECII, intense math calculation) they all have to wait for I/O to happen. But actually 25% of the cpu time, is spent switching between tasks, when these I/O holes occur. (All the registers, PC counter, everything has to be stored on the stack and then in virtual memory... then load from memory all the registers, stack, etc into the state they were in when the particular program being loaded was last stopped.

There is just too much waiting.