Testing the Beast

Got to working the quad-core PC with AutoCAD 2008. The 64-bit WinVista box is on the left side and displayed on the screen, four little boxes showing the four cores. The 32-bit WinXP box is on the right side. Monitor is a Dell 24" LCD running 1920x1200 resolution. And, yes, that's a Palm Vx plugged into the XP box - it's still functioning after seven years of use.

Tried working a normal course of activity on the quad-core by modifying drawings as I needed. Set AutoCAD to save files in the2004 format to maintain compatibility with the program on the other box.

AutoCAD and 64-bit WinVista work well together. Getting accustomed to a new OS and CAD program result in a few glitches but once I understand where things have moved and the "correct" way to access a particular function, CAD work is just fine.

Did a stress test using 100 mechanical drawings (all HVAC stuff) on a high-end resort spa project in the mountains west of Denver. The drawings consisted of full floor plans at small scale, partial floor plans at 1/8" scale, enlarged plans of residential units - four to sheet, equipment schedules, details, and diagrams for piping and duct risers.

Using AutoCAD's Sheet Set Manager for the first time was actually pretty easy. I goofed up the first attempt, realized my mistake, erased it and started over within five minutes. Another five minutes and I was ready to plot 100 DWF plans into a single electronic file.

AutoCAD 2008 ran through the plot session just fine without stopping. Speed was not much different from that experienced on the dual-core 3Ghz PC. I didn't bother to time the event as real judgement of speed was the perception of how it ran rather than clock time. Loading on the four cores was a bit uneven throughout the session.

I then remembered that AutoCAD has for years recommended that one does not allow Windows to manage virtual memory (the paging file or swap file.) Instead, they recommend fixing the paging file to maintain the maxium memory size indicated. From startup, AutoCAD itself does not play well with RAM and it's constantly swapping out data to virtual memory.

Back with AutoCAD R14, the memory size was advised to be 4 times the amount of RAM installed on the PC. In the XP box, I set the paging file at twice the installed 2GB RAM. For the Vista box, I set it to 6GB (1.5 times the 4GB RAM installed) and ran the test again. The 100-drawing test ran noticeably faster, between 30-50% faster, and the loading of the four cores was much better. Load seldom exceeded 50% for any real length of time. The drawings showing residential unit plans took more time to plot that other drawing types. I guessing that is because there were at least two and up to four architectural floor plans used as external reference files (Xref) and that was increasing the files size that AutoCAD had to work with. RAM demand ran pretty steady throughout the plot session.

As expected, software issues arose with the need for 64-bit versions. There's a good hand-full or more of programs that we need that will not run. A couple others run in a modified mode that looks different but the reason is not exactly clear. Oddly, a couple programs run just fine when I expected them to have problems.

Out of the entire process it necessary to understand that the speed by which a computer runs AutoCAD is dependent upon CPU speed, RAM amount and video card. The more balance those three are in their relative capabilities, the better AutoCAD will run. Letting any one of those items run out to their greatest capability will not necessarily result in better speed. The program is only as fast as the weakest link. As in the above test, AutoCAD hovered around 1.5GB of RAM usage when a full 4GB was available. It still needed to swap out data to virtual memory on the hard drive so rotation speed will at times make a difference as could network speed especially when making plot files.

Lots of fun and I get to do all it weekend, too.