Ram and Final Cut Pro Questions...

4GBs is plenty for editing HD. DVCPRO HD tends to be a bit less resource hungry than HDV, but you should be fine either way. In fact, I don't think FCP can even use more than 4 GBs of RAM (Might even cap itself around 3.5 GBs, don't remember for sure). What more RAM will get you is better/faster performance while multi-tasking serveral resource intensive programs.

You don't need 8GBs to take advantage of the RAM speed. That is determined by the slot configuration. Have DIMMS in Slot 1 and 2 in both Risers. If you have 6 DIMMS, fill out one riser fully before adding to the other one.

A good way to determine if your system needs more RAM is to look at the "pageout" count under the System Memory tab in Activity Monitor. This will tell you how often the RAM is writing to the temporary paging file on your hard disk. If you have a high number of pageouts (in excess of the page-ins), you may need more RAM.

Do be aware, that working with video is probably going to produce pageouts no matter how much RAM you have. To truly tell if your system is choking, open up Utilities -> Terminal and type "top" at the command line. In the top section of the listing, you'll see the same number of pageouts, along with a number in parenthesis. That number is the number of pageouts in the second. If it is high (25-50+) when working with your apps, you need more memory.




If you have an excessive number of page outs under

Mac Pro 2.66Ghz - 3GBs RAM - X1900XT Mac OS X (10.4.8)

slots 1 and 2 on both risers having matched kits is ideal.
nothing wrong with putting the 4 x 512s in slots 3 and 4 on each.

quad channel yields 256-bit data path.

Well, the system came with 4 X 512MB of Ram, so I'm
getting 2 x 1GB of Ram in the mail. That'll give me
6 DIMMS. I could've sworn that I had to match DIMMS
top to bottom for it to work. But you're saying to
put 4 DIMMS to fill up the top tray and then just
place the remaining 2 DIMMS on the bottom tray? Am I
understanding that correctly?

Yes. Each riser board has two pairs of slots, numbered 0 through 3. You MUST match 0 and 1 with the same type and size of RAM if you fill those slots on a board, and you MUST match 2 and 3. Otherwise, you can put whatever pairs you want on whatever boards.

Performance-wise, though, you get the best results by:

1) Filling both RAM boards' 0 and 1 slots with the same size and type of RAM. Same with 2 and 3 on both boards.

2) Placing dual rank (usually 1GB or higher capacity) RAM in 0 and 1 on both boards, as those are the slots that are usually hit first, and dual rank RAM is faster.

If you can afford it, you might consider getting an additional 2x1GB pair of the same brand you already have. Then, you could put those 4 modules in the 0 and 1 slots on each board and the 512 modules in 2 and 3. This will put your faster dual-rank RAM in the lower numbered slots, and will make sure that module sizes are matched across boards, which will maximize performance.

Also, I tend to have a lot of software open when I
edit. Soundtrack, Motion, Livetype, FCP, soon CS3
and other random software is usually open when I edit
(like iChat and Mail). Will 4GB still be enough you
think? I didn't mention all that in my first post,
so I apologize.

If you're running all of that, you might well find that extra RAM is helpful, particularly if you're processing in the background. Even if not, switching between applications will be smoother and faster with more RAM. This is another good reason to think about getting another 2x1GB pair.

Also, this whole Ram bandwidth thing has me confused.
If I do end up getting 6GB of Ram (4 x 1GB and 4 X
512MB)does that slow down my Ram? Does the fact
that I have 2 different types of DIMMS slow down my
Ram? It's all so confusing 😟

A tiny little bit that you may not notice, and no.

Right now you have 4x512MB in your 0 and 1 slots. This is pretty optimal for a setup of 512 MB modules, because having the same type of RAM paired across boards in the same numbered slots increases your memory performance.

If you add 2x1GB in the 2 and 3 slots on one board, your existing memory (the original 4x512MB modules) will still be able to transfer data at just as high a rate as before. The 2x1GB modules in 2 and 3 will be slower because they're not paired with another 2x1GB pair on the other board, but that will only affect accesses to the data stored in those modules, which the system will tend to use last.

What will slow down somewhat is that each request the CPU makes to transfer data from your existing 4x512MB RAM will take a bit longer to start because you have put modules in the 2 and 3 slots on one of the boards. Once it gets going, the transfer will happen at just as high a rate, but the setup time is longer by a small amount.

Chances are, the performance improvement you'll see with the extra RAM running all those apps will totally overwhelm any such slowdown. Note that I don't know of anyone who's benchmarked a real impact of that, all the discussions I've seen about such a slowdown are just theory.

However: those 1 GB modules in 2 and 3 will operate at a slower rate than they could because you don't have another 1 GB pair on the other board matched up with them. That's why I suggested getting a 2nd pair of 1 GB modules for the other board.

Finally, if you do get 4x1GB, swapping those 1 GB modules into the 0 and 1 slots will ensure that they get used first, and since most 1GB modules are substantially faster than the 512 MB modules, you'll want that for best performance. However, unless you get a couple of additional 1 GB modules to fill out the set of four, I would not recommend swapping the 512 MB modules into different slots. The fact that you have a matched set of 4x512 in slots 0 and 1 is a big speed benefit if you don't get a matched 4x1GB set for your expansion.

I hope that I haven't confused the situation... 🙂

-- Mark


4-core 3 GHz Mac Pro w/ 4.5 TB HDD and 10 GB RAM, 17 Macbook Pro 2.16 GHz

For Final Cut Studio the sweet spot, to me at least, is 8GB RAM plus the ATi X1900 XT.

PS Did you ever end up fixing your Parallels issues?

Thanks for the kind words. I also recommend reading this article, which discusses how to configure memory in Mac Pros based on real-world tests:

What Everyone Needs To Know About Mac Pro Memory Upgrades

-- Mark