Dual Core CPUs

[Danoff]

Alright, it's starting to get closer to time for me to upgrade my machine. But I have questions.

The biggie is how good dual core CPUs are. I've seen the benchmarks, and honestly I don't care about eeking that last extra few seconds out of an archiving task or getting those few extra fps out of my game. What I care about is the computer equivalent of low-end torque. I want my machine to be punchy off the line.

Windows sucks - but its the best thing we have right now, so that's what I'll be running. One thing windows is particularly bad at is multitasking. From what I can gather, the CPU manufacturers have started designing CPUs that help windows out by doing the multitasking for the operating system.

Back in the day, I always loved dual processor machines, because windows had a lot more multitasking firepower when it had two CPUs to throw jobs at. I loved the fact that I could be hammering away with some kind of CPU intensive task and windows wouldn't freak out when I started up another one.

So after that long-winded intro, here's my question to you folks that own a dual core CPU - does the machine respond as though you had two CPUs? Or does it still halt up and freak out when you give it too many jobs to handle?

Have multi-CPU PCs (not servers) been rendered obselete by dual core builds? Or is there still a reason to overpay for that dual CPU MB?

 

[Pako]

Alright, it's starting to get closer to time for me to upgrade my machine. But I have questions.

The biggie is how good dual core CPUs are. I've seen the benchmarks, and honestly I don't care about eeking that last extra few seconds out of an archiving task or getting those few extra fps out of my game. What I care about is the computer equivalent of low-end torque. I want my machine to be punchy off the line.

Windows sucks - but its the best thing we have right now, so that's what I'll be running. One thing windows is particularly bad at is multitasking. From what I can gather, the CPU manufacturers have started designing CPUs that help windows out by doing the multitasking for the operating system.

Back in the day, I always loved dual processor machines, because windows had a lot more multitasking firepower when it had two CPUs to throw jobs at. I loved the fact that I could be hammering away with some kind of CPU intensive task and windows wouldn't freak out when I started up another one.

So after that long-winded intro, here's my question to you folks that own a dual core CPU - does the machine respond as though you had two CPUs? Or does it still halt up and freak out when you give it too many jobs to handle?

Have multi-CPU PCs (not servers) been rendered obselete by dual core builds? Or is there still a reason to overpay for that dual CPU MB?

Unfortunately you won't find a noticeable performance increase unless you use applications that support dual core processors. In just the last year more applications are becoming dual-core friendly. What makes this a nice marriage is the move for 64-bit applications as well. In a perfect world, you will find a application that supports dual core efficiencies as well as being written for the 64-bit OS native.

I can say that running the 4800+ DC machine on Windows 64-bit, I only get the Windows splash screen for three sliding bars, one second is spent drawing the desktop and I'm ready to go. A 4 second boot to desktop isn't bad.

 

[donbenni]

I don't know if this helps in any way, but i just performed a very informal test to see how my computer would preform with multi programs running.

My specs are Asus mobo, 4800+ X2, 2G ram.

http://img.photobucket.com/albums/v292/donbenni/8620e2b9.jpg

The tasks running in this screenshot are:

Mozilla Firefox
Windows Media Player
Adobe Photoshop CS2
Adobe ImageReady CS2
Internet Explorer
Task Manager
Battlefield 2
Steam
Creative Audio setup thingy
Disk Defragment
+ all other processes running in the task bar and all background process

The Task Manager shows a total of 57 processes running with a CPU usage of 1%. The large spikes visible in the right hand graph are due to me starting the disk defragment (3 tall spikes in a row) and then switching over to Battlefield 2 (large single spike).

Switching between applications was instantanious. Switching to BF2 and the back to Windows was instantanious. On my old PC, alt+tabbing out of a game stalled the computer for a while, not here; not even an hourglass.

This computer slows down for nothing and i'm certain that's due to the dual processor.

And yes the fact that i can now encode my DVDs to DivX at over the twice the speed i could before keeps me up at night

I hope this was at least something like what you were after

 

[Danoff]

Unfortunately you won't find a noticeable performance increase unless you use applications that support dual core processors. In just the last year more applications are becoming dual-core friendly. What makes this a nice marriage is the move for 64-bit applications as well. In a perfect world, you will find a application that supports dual core efficiencies as well as being written for the 64-bit OS native.

I can say that running the 4800+ DC machine on Windows 64-bit, I only get the Windows splash screen for three sliding bars, one second is spent drawing the desktop and I'm ready to go. A 4 second boot to desktop isn't bad.

Thanks Pako. I'm not really talking about boosts in any individual application but a smoothing of running lots of applications - even if none of those apps support dual cores.

This computer slows down for nothing and i'm certain that's due to the dual processor.

You mean Dual Core right? What about when you punch "My Computer", does it hang for a moment while it checks out your CD drives or do you just cruise on?

Have you used a CPU that's of similar speed to yours on a similarly set up computer that isn't a dual core and noticed a difference with many applications up? I'm trying to figure out if Windows has just gotten better of multi-tasking (don't think so), or if this DC business really takes the place of multiple CPUs.

 

[Pako]

Thanks Pako. I'm not really talking about boosts in any individual application but a smoothing of running lots of applications - even if none of those apps support dual cores.



You mean Dual Core right? What about when you punch "My Computer", does it hang for a moment while it checks out your CD drives or do you just cruise on?

Have you used a CPU that's of similar speed to yours on a similarly set up computer that isn't a dual core and noticed a difference with many applications up? I'm trying to figure out if Windows has just gotten better of multi-tasking (don't think so), or if this DC business really takes the place of multiple CPUs.

Some of the lag going into "My Computer" can be attributed to other things besides processor speed. Hard drives, networks drives (a big culprit to My Computer Window lag, etc...). Do you have your hard drives in idle? Do you use virtual drives (nero image drive, alcohol 120%, daemon tools, etc)? All contributing factors.

Thanks donbenni for that info. I have installed may apps as of yet, need to reformat the system with the Raptor drives in Raid.

 

[Danoff]

Some of the lag going into "My Computer" can be attributed to other things besides processor speed. Hard drives, networks drives (a big culprit to My Computer Window lag, etc...). Do you have your hard drives in idle? Do you use virtual drives (nero image drive, alcohol 120%, daemon tools, etc)? All contributing factors.

Thanks donbenni for that info. I have installed may apps as of yet, need to reformat the system with the Raptor drives in Raid.

Sure, the "My Computer" lag can be attributed to things like the CD drives spinning up, and the machine checking all of the available MB ports for everything that might be connected to it. I think there are even network checks to see if there are network drives mounted.

I just remember noticing that my computer didn't freeze upon clicking "My Computer" when I had two CPUs. I think that was probably due to the fact that one CPU was free to process additional clicks and mouse movements. I don't mean that it shouldn't take the CD drives a few seconds to spin up.

 

[Pako]

I understand what your saying now. Just wanted to make sure you were aware of those other factors.

 

[donbenni]

You mean Dual Core right? What about when you punch "My Computer", does it hang for a moment while it checks out your CD drives or do you just cruise on?

Have you used a CPU that's of similar speed to yours on a similarly set up computer that isn't a dual core and noticed a difference with many applications up? I'm trying to figure out if Windows has just gotten better of multi-tasking (don't think so), or if this DC business really takes the place of multiple CPUs.

Yes Dual Core, sorry! It's an Athlon X2.

When i open My Computer there's no delay.

I'm pretty certain that someone on this forum has a similar PC to mine but with an Athlon 4000 which is the single core equivalent. I'll have a look around.

I think that dual core processors are essentially just two processors crammed onto one die.

 

[Pako]

You might want to read this excellent article:
http://www.tomshardware.com/2005/11/07/single/

 

[Danoff]

Ok, right now I'm thinking the X2 3800 is the way to go for me. Maybe the 4200. That article made it look like the dual core design was even better than two of the same processor (speedwise, not dual core) in a 2 CPU configuration. I don't quite see how that's possible, but that's what it looked like.

The article should have had two tasks running - like kicking off multiple zip archives or something - so that we could see which one was better at mutli-tasking.

 

[DQuaN]

Just a silly thought i had.

Is it possible to have a dual core dual processor setup?

 

[F1GTR]

Is it possible to have a dual core dual processor setup?

Yes, AMD opetrons have a dual core model and ASUS have a mobo that supports 2 Opetrons.

 

[donbenni]

Ok, right now I'm thinking the X2 3800 is the way to go for me. Maybe the 4200. *snip

The 3800+ X2 is terrific value when compared to the 3800+. The X2 is about £20 more expensive, which really isn't much.

The price hike to the 4200+ X2 seems perhaps a little too much to warrant what appears to be only a 200 Mhz increase.

 

[Danoff]

The 3800+ X2 is terrific value when compared to the 3800+. The X2 is about £20 more expensive, which really isn't much.

The price hike to the 4200+ X2 seems perhaps a little too much to warrant what appears to be only a 200 Mhz increase.

Yea that's what it looked like to me too. I've been looking at MB's that support this CPU, and it looks like the Asus A8N SLI Deluxe will do nicely, but then on the website they don't give me a good feeling for what ram is supported. They list some crazy super expensive Corsair stuff as being the Ram of choice.

Along the lines of what you said, pricewatch is listing the Athlon 64 X2 3800+ for $295 and the Athlon 64 3800+ as $275. That's a no brainer - especially if THG is right in that the X2 is better than 2 of the other.

 

[emad]

Ok, right now I'm thinking the X2 3800 is the way to go for me. Maybe the 4200. That article made it look like the dual core design was even better than two of the same processor (speedwise, not dual core) in a 2 CPU configuration. I don't quite see how that's possible, but that's what it looked like.

Those two chips are nice, but ideally, you'll probably want the x2 4400+ if your budget allows it. The 1mb of l2 cache is pretty useful for some of the more processor intensive programs.

 

[Omnis]

Yes, AMD opetrons have a dual core model and ASUS have a mobo that supports 2 Opetrons.

G5 Quad.

 

[Danoff]

Those two chips are nice, but ideally, you'll probably want the x2 4400+ if your budget allows it. The 1mb of l2 cache is pretty useful for some of the more processor intensive programs.

Ew. That's a bit of a jump in price. I'm not sure this is an ideal situation.

 

[skip0110]

You NEED memory, I have a 4200+ X2 with 512 MB (since Sept/05) and it's still pretty laggy..takes about 3-4 minutes to get to the desktop form boot and hangs for about 15-20 sec when alt-tabbing out of a game. I do a lot of development, and having Visual Studio, MSDN help, Opera, a MP3 player, and 3-4 Explorer windows really makes it feel quite slow.


EDIT: THG is right, the X2 has shared cache which helps over a regular SMP setup is a process switches from one core to another or two processes use the same dll...

 

[Event]

I would think that 2 individual CPUs would be better, since each individual CPU processor has it's own bus, while the dual-core has to share its bus between 2 cores.

 

[skip0110]

I would think that 2 individual CPUs would be better, since each individual CPU processor has it's own bus, while the dual-core has to share its bus between 2 cores.

But every time a piece of memory goes into cache on both CPUs, it might be out of sync between them if a computation is done on it on one CPU. Or, if memory is cached on one CPU but not written back yet (this normally doesnt happen until that part of cache needs to be overwritten, at least on x86 and RISC arch CPUs) then the other CPU might read the memory, which is actually out of date when it should really be looking in the other CPUs cache. (I hope I explained that okay)

So what happens is every time one CPU needs something from memory, it has to ask the other CPU if it has a more up to date version, and that other CPU has to stop what it's doing and respond (what actually happens is the processors have to continually exchange synchronization bits to make sure their caches are kept in sync) so basically the caching is rendered null-and-void, and every cycle requires bus access, which is slow as dirt compared to going directly to the cache. But if they share cache then about 80% of the time the bus doesnt get involved--thus faster.