920XM vs. 620M for Adobe Lightroom

I currently have a T9300 (2.5 Ghz Core 2 Duo). Far and away the place where my processor slows me down is with Lightroom, in particular, rendering previews when I import hundreds of photos after a shoot. This is going to take a bunch of time with any computer, but the faster the better.

For my desktop I'm set, but when I'm on the road, I'd like to upgrade my laptop. I'm looking at getting a laptop with either a Core i7 620M or a Core i7 920XM. The 620M has a 2.66 Ghz primary clock speed, which is 33% faster than the 2Gz on the 920XM. They both turbo boost to similar speeds. The 920XM uses *much* more power, but I can live with that.

When I import photos in Lightroom and render 1:1 previews (necessary for making it speedy when viewing photos), the preview rendering pins my current processor at 100% for both cores for about 20 seconds /photo (so for the size imports I usually do, 45 minutes to an hour). I expect the 920XM would speed this up meaningfully, as even though it has a 20% slower clock speed than my current T9300 processor, it has twice as many cores (and is a newer generation technology). Is this right, or would the 20% slower clock speed more evenly balance out the performance gain on Lightroom's photo importing than I think? How would the 620M's 33% faster primary clock speed compare to the 920XM's 100% more cores for this application? Obviously answering this question requires someone who has some experience with how well Lightroom scales on a multi-core processor.

The other aspect of Lightroom that is a chore is the rendering of photos at the time of editing. In particular, when I'm pasting settings to photos, the lag before I can start editing (pasting) gets painful. Am I right both that (1) the rendering process here is not sped up at all by the graphics processor, so that is a non-issue and (2) although I assume rendering a single preview is a single threaded action, the 620M and 920XM would be about equally quick for this, because although the 620M has a faster clock speed, they both turbo boost to the same speed and presumably the 920XM can maintain turbo boost for long enough to render a single photo.

Anyone who has any knowledge about this, I would very much appreciate your sharing!

 

You know a T9300 and a i7 are not interchangeable?

How much it would improve depends on Lightroom - can it efficiently use a quad core?

 

I do know they aren't interchangeable -- I'm getting a new laptop. I have read in many places that Lightroom uses a quad core effectively, but the question really is whether a slower quad core is better for this purpose than a faster dual core. So I think really I need someone with Lightroom-specific experience to help me here.

 

Well, if Lightroom is able to use a quad core effectively then it will definitely be faster than a dual core - simply because it can work on 4 thread at the same time - rather than one, depending on how exactly it works.

(Split one image into several RAW files, or 1 image per Core?)

How much improvement you see - there are too many factors really...

 

Can't you ask/mail the developers of lightroom (support) if the program is supporting multi-threading? If so you would be better of with the i7-920XM, because it can actually handle 8 instead of 4 threads (which the 620m max. can).

 

The question here is - what's better 1 real and 1 virtual threads or one real thread that's faster - hyperthreading doesn't have to be better.

But its a good idea.

 

620m vs 920xm
35w vs 55w
32nm vs 45nm
4mb cache vs 8mb cache

Also the 620m has a slower memory spec and as a result less memory bandwidth. But the tradeoff for the 920xm is that you'll be on the old clarksfield 45nm platform, where with the 620m you'll be on the new Arrandale 32nm platform. Both have 4 real cores and 8 virtual threads through hyperthreading. Also both have turboboost, and the 620m supports ALL of the new Intel features such as AES instructions and sse4.2

 

the 920XM should be better as it has 4 cores and 8 threads and especially in a multi threader app , it would be great... but its expensive... i recommend that u get the 820QM at most..

 

Unfortunately, the i7-620M only has 2 real cores and 4 virtual threads through hyperthreading.

 

Whoa, yea, sorry about that..lol.. the 620m does have 2 real cores and 4 virtual threads... *amn DayQuil...

 

If you haven't seen this benchmark thread yet