A blow to Apple’s US-Euro Mac relations could be caused by cache and video-card differences in the US 500MHz iMac and its European equivalent. On the cache side, it’s not known on which side the difference works out for the better. But the European mid-range iMac is definitely worse off when Apple came to handing out video cards.

In the US, the mid-range iMac boasts 256K on-chip level-2 cache at full processor speed (500MHz; a speedy 1:1 ratio). In Europe, that same machine has twice the amount of backside level-2 cache (512K) but at the slower 200MHz (a slower 2.5:1 ratio). We didn’t have units of the US model to test against the European mid-ranger so we can’t yet say whether this makes one marginally faster than the other. But in previous tests, we did find that cache plays a not insignificant part in the overall speed of a system.

The 400MHz iMac (512K backside level-2 cache at 160MHz) and 600MHz iMac (256K on-chip level-2 cache at full processor speed) are the same on both sides of the Atlantic.

Video killed the Euro star The European 500MHz iMac – available in Indigo, Flower Power and Blue Dalmatian - is rather blighted when it comes to video graphics. In the US, it ships with a 16MB ATI RAGE 128 Ultra video card. In Europe, it has the lower-performance 8MB ATI RAGE 128 Pro (the same card as in the entry-level iMac). The European Special Edition iMac (600MHz) ships with the 16MB Ultra card, as it does in the US.

This will affect frame rates in games such as Quake III, and could result in slower scrolling. Most iMac owners wouldn’t notice the difference unless it was pointed out in a side-by-side comparison – but Apple can’t yet supply us with a reason why this discrepancy has arisen.

Read Macworld’s hot reviews of the new iMacs.