The new iMac G5's have some technical differences to previous generations of G5's
They are the first Macs to use DDR-2 RAM. This is not backwards compatible with DDR or vice-versa, so there is no swapping of memory going to happen as you upgrade. They are the first Macs to support a 2 Gb memory module -- which is a good thing because there is only one accessible memory socket. The developer notes are not up yet, so it is an open question whether the 512 RAM is available to be upgraded by a technician -- Apple does not offer that option as a BTO, and states maximum RAM as 2.5, which suggests not.
Currently, Apple's price on the 2 Gb module is insane: US$1200.
Third party RAM should be verified compatible with in the next week or so, and 2 Gb modules should be in the US$700 area.
With a single socket, there is no question of matching RAM pairs or not. Dual-channel is not on offer.
While DDR-2 RAM is theoretically faster than DDR, the latency of DDR-2 modules is a problem, the current modules can't go faster than a CAS Latency of 4. (DDR RAM is commonly CL3 or 2.5, with premium memory at CL2.0). This means some of the speed gain is wasted waiting for the RAM to be ready to accept the next operation. As the DDR-2 market matures, we can expect lower latency RAM to be come available in quantity and the price of the large modules to drop.
The differences between the models: The 17" has a ATI Radeon X600Pro video card and the 20" has an X600XT which is roughly 20% faster core speed - both models have 128 Mb VRAM. Although listed as PCI-Express , they do not specifiy that the video cards are removeable, so upgrades are likely still impossible.
The processors are 1.9 GHz and 2,1 GHz (10% difference) The 17" has a 633 MHz system buss, vs. 700 MHz on the 20" (also 10% in line with the CPUs, at a multiplier of 3). This compares with 1 GHz, 1.15 GHz and 1.35 GHz busses per processor (multiplier of 2) in the DP G5 towers. Clearly, the iMac is not going to challenge the G5 towers for heavy lifting.
Bluetooth and WiFi "g" are built in as expected. Sensibly, the telephone modem has been deleted and is available as a USB option. The hard drive is a straight SATA drive, no indication of SATA-II support. The wireless remote is infared, not RF, so it will be line-of-sight only. Makes sense though if it's primary purpose is controlling visuals. Both the 17" and the 20" have Dual-Layer Superdrives (DVD+/-RW) as standard, which is a nice boost on the original entry level machine.
What the iMac G5 does signal is that the next G5's are going to be based on new motherboards - the DDR-2 move will require a redesign of the motherboard and the busses. (and Wintel motherboards have been on DDR-2 for a number of months already). Hopefully, Apple will address the Firewire speed limitations of the G5 line at the same time.
Thanks
Trevor
CanadaRAM.com
They are the first Macs to use DDR-2 RAM. This is not backwards compatible with DDR or vice-versa, so there is no swapping of memory going to happen as you upgrade. They are the first Macs to support a 2 Gb memory module -- which is a good thing because there is only one accessible memory socket. The developer notes are not up yet, so it is an open question whether the 512 RAM is available to be upgraded by a technician -- Apple does not offer that option as a BTO, and states maximum RAM as 2.5, which suggests not.
Currently, Apple's price on the 2 Gb module is insane: US$1200.
Third party RAM should be verified compatible with in the next week or so, and 2 Gb modules should be in the US$700 area. With a single socket, there is no question of matching RAM pairs or not. Dual-channel is not on offer.
While DDR-2 RAM is theoretically faster than DDR, the latency of DDR-2 modules is a problem, the current modules can't go faster than a CAS Latency of 4. (DDR RAM is commonly CL3 or 2.5, with premium memory at CL2.0). This means some of the speed gain is wasted waiting for the RAM to be ready to accept the next operation. As the DDR-2 market matures, we can expect lower latency RAM to be come available in quantity and the price of the large modules to drop.
The differences between the models: The 17" has a ATI Radeon X600Pro video card and the 20" has an X600XT which is roughly 20% faster core speed - both models have 128 Mb VRAM. Although listed as PCI-Express , they do not specifiy that the video cards are removeable, so upgrades are likely still impossible.
The processors are 1.9 GHz and 2,1 GHz (10% difference) The 17" has a 633 MHz system buss, vs. 700 MHz on the 20" (also 10% in line with the CPUs, at a multiplier of 3). This compares with 1 GHz, 1.15 GHz and 1.35 GHz busses per processor (multiplier of 2) in the DP G5 towers. Clearly, the iMac is not going to challenge the G5 towers for heavy lifting.
Bluetooth and WiFi "g" are built in as expected. Sensibly, the telephone modem has been deleted and is available as a USB option. The hard drive is a straight SATA drive, no indication of SATA-II support. The wireless remote is infared, not RF, so it will be line-of-sight only. Makes sense though if it's primary purpose is controlling visuals. Both the 17" and the 20" have Dual-Layer Superdrives (DVD+/-RW) as standard, which is a nice boost on the original entry level machine.
What the iMac G5 does signal is that the next G5's are going to be based on new motherboards - the DDR-2 move will require a redesign of the motherboard and the busses. (and Wintel motherboards have been on DDR-2 for a number of months already). Hopefully, Apple will address the Firewire speed limitations of the G5 line at the same time.
Thanks
Trevor
CanadaRAM.com
