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tfortier
07-09-2006, 10:03 PM
Hi... I tried the same After Effects HD sized greenscreen scene on my job and home computers... my home comp is a vulgar 2.8ghz p4 2gb ram p4p800 mobo and my job one is a dell 3.4 ghz dual xeon 3gb ram. In previous test I notice the Dual Xeon was like 210% more fast that the 2.8 p4 with generic scene (no footage)... but now in a scene simply involving an HD footage layer with greenscreen key, a mask and a blur, the xeon become like 320% faster...

I presume the xeon motherboard get better bandwith for bring the footage faster to after effects but im sure both computer have normal 7200 rpm HD... can you explain to me what can cause such a dramatic performance boost with HD content in the xeon...

I plan to build a conroe dual core soon as they are out for an upcoming 2K very important side job then I dont wanna make mistake and get the best computer for the price... if Dual Xeon still give me the more bandwith... I really wanna know!

thanks a lot!
t

UrbanFuturistic
07-09-2006, 10:58 PM
OK, I was going to write a list of various possibilities but the main one is simply Hard Drive speed.

Even with 3GB of RAM, editing Raw HD footage is still going to involve a lot of reading of raw footage just for playing and pagefiles measured in the tens of GigaBytes.

So, if you've got a workstation with dual Xeons in, I'd imagine it might come with a decent Ultra2 SCSI controller, preferably setup with the drives in something like a RAID 0+1 for speed and data integrity.

Of course, the dual Xeons and the extra RAM do have an effect but not 210% :p but I think you already knew that :D

tfortier
07-10-2006, 12:37 AM
hi odubtaig, thanks for reply! there is no RAID in the dell workstation... It was a 2000$ deal (can$) and im quite sure its normal cheap Dell no name hard disk... we have a lot of problem with them... since few month more than 10 dies... but maybe my comp at home is old IDE hd at the opposite of SATA at job..?! oh... and I never defragment it too...

cooperunionstud
07-10-2006, 03:09 PM
well since your computer at work is a dual xeon. its already more that double the ghz of your pentium 4. 2.8ghz

3.4 x 2 = 6.8ghz

6.8 / 2.8 = 2.5 rounded.

thats 2.5 times of theoretical rendering speed over your pentium4 at home

just a side note i have two computers at home one is a dual core 4200 and another is 3.0ghz p4. during network rendering on 3d max i noticed that my dual core renders 3 frames for every 1 frame my 3.0ghz p4 does. so thats roughly 3 x the speed

lots
07-10-2006, 04:01 PM
Total speed of a dual core/CPU system != total combined MHz. You cant compare a dual CPU system with a single CPU system in this manner. There are always applications which will see large benifits due to multiple CPUs, and there are alawys applications which will see a performance hit for the same reason.

Additionally, two 3.4GHz CPUs still run at 3.4GHz, they dont magically combine to form an all powerful 6.8GHz CPU. Each CPU still runs at 3.4GHz.

Anyway, to answer some of the OP's question, improvements in performance are probably due to the speed difference on each CPU.



note: != is not equal in most programming languages :P

PanzerMKZ
07-10-2006, 05:44 PM
SSE3?



Panzer

lots
07-10-2006, 06:03 PM
Yeah, optimizations that the Xeon system may have that the older P4 chip doesnt could also explain some of the speed improvements.

tfortier
07-22-2006, 03:29 AM
damn! I finaly find out; my storage disk was in PIO, not DMA! I had to uninstall the primary IDE channel for fix it... no idea why it switched itself..!

anyway, now After Effects feel less stuttering previewing tose big HD clip!

Ill do a comparison test monday...

thanks

thierry

MassTA
07-22-2006, 08:33 AM
damn! I finaly find out; my storage disk was in PIO, not DMA! I had to uninstall the primary IDE channel for fix it... no idea why it switched itself..!

Windows switches data transfer to slower mode, when it detects errors during data transfer form the drive. It interpretes this, as the cable is bad, and switches to lower speed to make sure the connection is reliable. This usually happens when you put a badly scrached CD in your drive, and the CD/DVD-ROM cannot correct all the errors.

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07-22-2006, 08:33 AM
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