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gravityplan
Apr 19, 2004, 08:02 PM
Is 12" pb's bump from 266DDR to 333DDR a big deal? How will this affect performance?

slooksterPSV
Apr 19, 2004, 08:28 PM
Is 12" pb's bump from 266DDR to 333DDR a big deal? How will this affect performance?
The faster you can write to RAM, the faster your programs will be able to start. PC2700 (DDR333) RAM writes and reads at 2.7GBPS PC2100 (DDR266) writes and reads at 2.1GBPS

Capt Underpants
Apr 20, 2004, 07:39 AM
The faster you can write to RAM, the faster your programs will be able to start. PC2700 (DDR333) RAM writes and reads at 2.7GBPS PC2100 (DDR266) writes and reads at 2.1GBPS

So, unless you need more than 2.1 GB written or read to RAM in a single second, this upgrade isn't important? That kind of sucks. Think about it; the 12" powerbook only holds 1.256 GB of RAM. Am I thinking about this the wrong way, or something?

grapes911
Apr 20, 2004, 08:02 AM
It really doesn't matter how much ram you have in this case. Your ram is written to, read from, and re-writtern all the time. Now anything to and from the ram can be faster. I shouldn't say anything. It can go faster to and from cache. To and from the hard drive is still about the same becasue the hard drive is much slower than ram.

gravityplan
Apr 20, 2004, 11:26 AM
So, unless you need more than 2.1 GB written or read to RAM in a single second, this upgrade isn't important? That kind of sucks. Think about it; the 12" powerbook only holds 1.256 GB of RAM. Am I thinking about this the wrong way, or something?

The GB is probably for gigabits, not gigabytes (guessing- I could be wrong). Although either way that sounds really fast.

yamabushi
Apr 20, 2004, 11:47 AM
Yes, applications will run a bit faster. How much faster will depend on the particular application. The boost in RAM frequency combined with the boost in bus and cpu frequency will likely produce a noticeable difference when compared to the old model. The memory performance is best understood when mated to the performance of the bus and cpu.

The new 12" the bus runs at 166, the ram at 333(2xbus), and cpu at about 1333(8xbus). The old 12" bus ran at 133, the ram at 266(2xbus) and cpu at 867(6.5xbus) or 1000(7.5xbus). These numbers are important because you will not get much extra performance as you increase the speed of the cpu unless you increase the bus and ram speed.

The ratio of bus to cpu frequency is called the bus multiplier (8x in the new 12"PB). Ideally this number should be as low as possible in order to maximize the flow of data through the bus. Applications that use audio and video often are very demanding on the bus and can have problems if too much data tries to pass through this bottleneck.

The new 12" Powerbook manages a 33% boost to the cpu with only a slight increase to the bus multiplier - an impressive feat. No match for a G5 Powermac with its 2x multiplier but still quite good.