Dissecting Intel's top graphics in Apple's 15-inch MacBook Pro

The new 15-inch MacBook Pro Retina is being offered with Intel-only graphics. Is it up to the task?

Apple's new high-end 15.4-inch MacBook Pro uses Intel's most powerful graphics chip yet, the Iris Pro with integrated 'Crystalwell' eDRAM.
Apple's new high-end 15.4-inch MacBook Pro uses Intel's most powerful graphics chip yet, the Iris Pro with integrated "Crystalwell" eDRAM. Apple

For the first time, Apple is offering a 15.4-inch Retina MacBook Pro model with Intel-only graphics silicon. So what is Intel's best graphics chip yet, and how good is it?

That $1,999 MacBook Pro is powered by a quad-core Haswell Core i7 processor with Intel's Iris Pro 5200 graphics. (The high-end $2,599 MacBook Pro adds a standalone Nvidia GeForce GT 750M graphics processing unit to the 5200.)

Apple describes the 15.4-inch Retina MacBook Pro's Iris Pro as "128MB of embedded memory to accelerate processor- and graphics-intensive tasks by acting as an ultrafast cache."

Let's break that down. That means Intel has bolted, aka "embedded," 128 megabytes of memory onto the Haswell processor. And that discrete memory chip -- which Intel calls "Crystalwell" -- is used as a high-speed cache to boost performance.

Anandtech describes it as a fourth-level cache.

"Unlike previous eDRAM implementations in game consoles, Crystalwell is true 4th level cache in the memory hierarchy. It acts as a victim buffer to the L3 cache, meaning anything evicted from L3 cache immediately goes into the L4 cache. Both CPU and GPU requests are cached," according to Anandtech.

Crystalwell is only offered with Intel's quad-core Haswell, like the one in the 15-inch MacBook Pro.

That large helping of extra high-speed integrated memory is new ground for Intel in consumer products. Is this a new direction for the chipmaker? Let's hope so, as more and more consumer laptops are coming with Intel-only graphics.

And, importantly, all that native Intel silicon integration is easier on battery life than separate GPUs like Nvidia's.

Finally, it is worth mentioning the cluster of 40 execution units -- what Intel calls EUs -- that handle the graphics tasks in Iris Pro. Lower-end Haswell processors don't have as many GPU execution units.

How good is Iris Pro with Crystalwell? It's not a high-end Nvidia GPU, but it's not slow either.

"Iris Pro should...be competent enough to make modern gaming possible...Just because it's not as fast as a discrete GPU doesn't mean that it's not a very good integrated graphics solution," Anandtech said.

Intel's Iris Pro integrates eDRAM enabling discrete graphics level performance.
Intel's Iris Pro integrates eDRAM, enabling discrete graphics-level performance. Intel/via Anandtech
Anandtech
Editors' note: This post was originally published at 2:18 p.m. PT on October 24. It has been updated throughout.
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