Apple's iMac May Receive AMD CPU

The Apple rumor is that everyone’s favorite tablet maker is considering AMD for a spot in the Mac lineup. AppleInsider claims that AMD executives have been pitching Apple on the chipmaker’s upcoming product roadmap, and that the two parties are in “advanced discussions” about putting AMD processors inside some of Apple’s products.

At first the rumor might seem pretty silly, the Mac is a premium PC family at a premium price, so there really isn’t a place for a value vendor like AMD in it. Or is there? Strange things have happened and Apple can’t be too happy about having its 13” MacBook Pro caught in the crossfire of the Intel/NVIDIA DMI bus licensing dispute. As we’ve seen time and time again, Apple likes to have options.

It certainly makes sense that Apple would have regular talks with alternate suppliers for a critical part of its platform, that’s just good business. If Apple issues a nondenial denial of the AMD rumor, then they may be trying to put pressure on Intel to shape up. Furthermore, since Intel is no longer allowed to essentially pay computer makers to use its chips exclusively and Apple never got market rebates from Intel anyway because it doesn’t participate in Intel’s logo program, Intel doesn’t have any real financial leverage on Apple. Given Apple’s relationship with ARM and NVIDIA, AMD is the only major Intel competitor that’s missing from its product mix.

Therefore, its perfectly reasonable to believe that Apple and AMD are having some sort of talk and there are no consequences for using one of Intel’s rivals for some of its CPU needs. The big question is, where could Apple find a place for AMD in its lineup.

AppleInsider speculates that AMD may end up in Apple’s portables, but that’s just crazy talk. Apple has spent a lot of engineering effort on getting its own new version of NVIDIA’s Optimus technology out of the door. At the end of the day, the hacked-up Optimus-like solution that Apple has for portables now is actually great from a performance/watt perspective for mobiles. It combines the leading performance/watt mobile CPU with a leading mobile discrete GPU, and it’s a shame that the solution doesn’t fit into the 13” MacBook Pro. AMD/ATI would not have been able to offer an IGP + discrete GPU switching solution that matches it in terms of performace and power efficiency (though an AMD-designed alternative would have been cheaper for Apple.) The place where Intel’s strategy of putting an IGP/nortbridge in the same package as CPU is a problem on the desktop.

Where To Put AMD CPUs? The iMac

Given that Intel has the performance crown for servers and the performance/watt crown in mobile, the most likely place for Apple to use AMD is in the iMac. Right now the iMac is still on the 45nm Core 2 Duo. The obvious Intel replacement for the iMac’s C2D is Intel’s dual-core, 32nm Clarkdale family, either the Core i5 or the Core i3, both of which have been out since the start of the year. But the new Core i5 Clarkdales don’t really improve on the older quadcore, 45nm “Lynnfield” part that are currently in the 27” iMac.

The entire Clarkdale family has two features that Apple and anyone else looking for maximum performance and minimum waste is going to hate, one being the memory controller has moved back off the CPU die and two, there’s an IGP and northbridge in the package with the CPU. The off-die memory controller means that Clarkdale’s memory latency stinks and the in-package GPU/northbridge means that you are paying for a sub-par Intel IGP that you really don’t want to use if you’re building a performance desktop.

The upside of all this is that, with possible exception of HTPC builders, anyone who is considering putting Clarkdale in a performance or mid-range desktop would really be better off with a quad-core CPU from AMD including Apple. The cheaper, 32nm, non-Lynnfield part of the Core i5 lineup just isn’t that attractive right now.

We aren’t claiming that we’ll actually see an AMD-based iMac, but it wouldn’t surprise us if we did. Intel has left the door open for AMD’s Phenom X4 to walk right through, and it’s possible that Apple will go ahead and invite the X4 in.