Historically, Apple does have a fall notebook refresh, but with so many notebook refreshes this year, I'm wouldn't be surprised if we don't see one. Certainly, it'd seem in Apple's best interest to wait for Arrandale which is due next year, although it's possible they'll split the product line with Core 2 Duo and Core i7 like they did in the iMac although that is a lot of extra design work unlike Arrandale and Clarksfield which can share chipsets.
Seeing the LCD manufacturers are pushing toward 16:9 displays, even if I hate it, I think there's not that much Apple can do to stem the tide without having to pay more for 16:10 displays as volume production moves toward 16:9. As such it wouldn't surprise me to see Apple move to 14" 1366x768, 15.6" 1600x900, and 17.3" 2048x1152 displays. Still with this change, maybe they can bring back the ExpressCard slot for the 15" model.
Assuming Apple convinces Intel to give them Arrandale early for a November MacBook Pro refresh, my guess on a lineup would be as follows:
14.0" 1366x768 Low-End MacBook Pro
~2.26GHz Core i5 Arrandale with 3MB L2 cache (OEM model like current 2.26GHz Core 2 Duo)
2GB DDR3 1333MHz
250GB HDD
Intel GMA + nVidia GT210M with 256MB GDDR3
14.0" 1366x768 High-End MacBook Pro
2.4GHz Core i5-520M Arrandale with 3MB L2 cache
4GB DDR3 1333MHz
320GB HDD
Intel GMA + nVidia GT210M with 256MB GDDR3
15.6" 1600x900 Low-End MacBook Pro
2.4GHz Core i5-520M Arrandale with 3MB L2 cache
4GB DDR3 1333MHz
320GB HDD
Intel GMA + nVidia GT210M with 256MB GDDR3
ExpressCard Slot
15.6" 1600x900 Mid-End MacBook Pro
2.53GHz Core i5-540M Arrandale with 3MB L2 cache
4GB DDR3 1333MHz
320GB HDD
Intel GMA + ATI 4830 with 512MB GDDR3
ExpressCard Slot
15.6" 1600x900 High-End MacBook Pro
2.66GHz Core i7-620M Arrandale with 4MB L2 cache
4GB DDR3 1333MHz
500GB HDD
Intel GMA + ATI 4830 with 1GB GDDR3
ExpressCard Slot
17.3" 2048x1152 MacBook Pro
2.66GHz Core i7-620M Arrandale with 4MB L2 cache
4GB DDR3 1333MHz
500GB HDD
Intel GMA + ATI 4830 with 1GB GDDR3
ExpressCard Slot
Both the High-end 15" and the 17" MacBook Pro can have the 1.73GHz Core i7-820QM as a BTO. Given the low clock speeds of the 1.6GHz Core i7-720QM especially in dual core mode where it can only Turbo to 2.4GHz, I can't see Apple being very enthused with using it, since you could actually lose performance in the average dual core application compared to current 2.66GHz+ Core 2 Duos in MacBook Pros. So I didn't include the Core i7-720QM Clarksfield as a regular configuration even though it's priced similar to the Core i7-620M Arrandale.
I don't see USB 3.0 since there is no chipsets with integrated support and I don't see Apple devoting motherboard space for dedicated chips. It's still early for fibreoptic connections. I'm hoping for Firewire 3200 and Bluetooth 3.0 though. The 15" MacBook Pro would hopefully see the return of the ExpressCard slot and all models would still have SD slots including the 17" MacBook Pro which currently doesn't. It'd be interesting to have bi-directional Displayport support too, although it would be kind of a niche feature. Apple could also use the presumably extra width of a 16:9 transition to put in 4 SODIMM slots like in the iMacs. That would better allow 8GB configurations in a 4x2GB configuration to avoid paying the high prices for 4GB SODIMMs. Although I don't think many laptops have 4 SODIMM slots.
For graphics, I figured that combining Intel GMAs with at least a dedicated low-end GPU is a good compromise for OpenCL support. Intel GMAs do support dynamic GPU switching. AppleInsider reports references to the Mobility Radeon 4500 series which would be a disaster as the replacement for the 9600M GT since it's actually slower and meant as a low end GPU. An alternate GPU arrangement to what I proposed to incorporate this rumour would be to replace the nVidia GT210M with the HD4530, which would be slower, knowing Apple that makes it more likely, but still an improvement over the 9400M. The HD4830 is an aggressive choice being 40nm for mid-range GPU power consumption for the 15"/17" models and not very likely since it's so rare, so I'd settle for a nVidia GT240M (still DX10.1 compliant) or the faster Mobility Radeon HD4600 series. It wouldn't surprise me either if Apple stuck with 256MB and 512MB VRAM configurations.
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