Core i5 vs. Phenom II X4 CPU Review

Posted By Gabriel Torres on Sep 29, 2009 in CPU

Introduction

Core i5-750 (2.66 GHz) from Intel is costing today USD 200 and AMD doesn’t have any Phenom II X4 at the same price tag. The closest matches are Phenom II X4 955 Black Edition (3.2 GHz), costing USD 189, and Phenom II X4 965 Black Edition (3.4 GHz), costing USD 245 – which are the fastest CPUs from AMD –, putting Core i5-750 in the middle of the two in terms of price. But how about performance? Which CPU is faster, Core i5 or Phenom II X4? Let’s see!

Both Core i5 and Phenom II X4 have an integrated memory controller supporting DDR3 memories up to 1,333 MHz in dual-channel configuration. One of the main architectural differences between Core i5 and Phenom II X4 is the presence of an integrated PCI Express 2.0 controller on Core i5, which in theory improves the practical transfer rate achieved by video cards. This controller provides 16 lanes, meaning that it can be connected to one video card working at x16 or to two video cards working at x8 each. On Phenom II X4 the PCI Express 2.0 controller is located on the chipset from the motherboard.

Another feature present on Core i5 and not available on Phenom II X4 is Intel Turbo Boost technology, which is essentially an automatic overclocking made by the CPU when it “feels” that the program needs more processing power (this is done only when the CPU has some of its cores idle and the total CPU temperature and thermal dissipation is still within specs).

AMD CPUs talk to the external world (i.e., the chipset) through a bus called HyperTransport (working at 8 GB/s on the two models we included in this review), while Core i5 use the DMI (Digital Media Interface) bus to talk to the chipset (working at 2 GB/s), which is the interface previously used to make the connection between the north bridge and the south bridge chips on Intel chipsets. At a first look it seems that AMD has the advantage here, but since Core i5 talks directly to the main video card without using its external bus and without using the chipset, this solution seems adequate.

On the tables below we compare the main specs from the CPUs we included in this review.

CPU	Cores	Internal Clock	Turbo Clock	External Bus	Base Clock	Core	Technology	TDP	Socket	SSE4	Price
Core i5-750	4	2.66 GHz	3.20 GHz	2 GB/s	133 MHz	Lynnfield	45 nm	95 W	1156	Yes	USD 200
Phenom II X4 955	4	3.2 GHz	–	8 GB/s	200 MHz	Deneb	45 nm	125 W	AM3	No	USD 189
Phenom II X4 965	4	3.4 GHz	–	8 GB/s	200 MHz	Deneb	45 nm	140 W	AM3	No	USD 245

TDP stands for Thermal Design Power which advises the user of the maximum amount of heat the CPU can dissipate. The CPU cooler must be capable of dissipating at least this amount of heat.

The prices listed were researched at Newegg.com on the day we published this review

CPU	L1 Cache	L2 Cache	L3 Cache	Memory Support	Memory Channels
Core i5-750	32 KB + 32 KB per core	256 KB per core	8 MB total	DDR3 up to 1333 MHz	Two
Phenom II X4 955	64 KB + 64 KB per core	512 KB per core	6 MB total	DDR3 up to 1333 MHz	Two
Phenom II X4 965	64 KB + 64 KB per core	512 KB per core	6 MB total	DDR3 up to 1333 MHz	Two

Pay attention as on the Phenom II X4 box the manufacturer says “8.0 MB Total Cache;” AMD has obviously added the values of L2 (4x 512 KB) and L3 cache (6 MB) to reach this figure.

Now that you know the contenders, let’s see how they performed.

Since we have the data from several other Intel CPUs we collected for our Core i5-750 and Core i7-870 review, we will add them also to our charts, but on the text we will be exclusively comparing the performance of Core i5-750 and the two top Phenom II X4 CPUs from AMD.

Continue: How We Tested