Kunal Rupera | 15 October 2007
Intel has become a second name to processors from the point of view of a common man. The Indian desktop market relies on the reputation and awareness of a brand for making purchasing decisions. That is probably why in spite of having a superior processor lineup for almost four years, AMD was not able to capitalize as a market leader in India as much as it did in the international markets. Although Intel enjoyed market domination in the subcontinent, with its NetBurst architecture, it went on a clock speed frenzy with its Pentium 4 line of processors. Higher frequencies did not necessarily mean higher performance as these processors did not perform as well as their AMD counterparts, which were clocked at much lesser frequencies. Besides, higher frequencies led to greater heat generation. The Pentium 4 Prescotts were popularly referred to as Pres“hots” because of the enormous amount of heat they generated. In the last two years, AMD gathered ground with their 64-bit platforms—the Socket 754 and the Socket 939. Their Duron series of processors were considered great value for money while their Athlon 64 series became the de facto standard for gamers and multimedia content creation users. Their Athlon 64 FX-62 was the reigning king. That is until Intel launched their Core 2 Duo family of processors on July 27, 2006. Before we get into the technical details of the processor, let us look at Intel’s current product lineup. The table overleaf lists their desktop line of processors.
What makes the Conroe tick?
Intel learnt from its mistakes and got back to the drawing board. This time around it derived its inspiration from Yonah (Core Duo), the mobile platform used for laptops. The new Woodcrest (servers), Conroe (desktops) and Merom (laptops) are all based on the Yonah but nearly 80 percent of the architecture and the circuit design has been redone. Like the Yonah, Conroe too uses the 65 nm manufacturing process. Intel has also addressed the heat problem and the Conroe uses a TDP (Thermal Design Power) of 65 watts compared to the 89 watts for AMD’s Athlon 64 FX-62. It is almost half of that used by Intel’s previous generation lineup. Intel has managed to run its processors cool using the least amount of power. Now coming to whether Conroe will perform up to the mark or not, let us first take a look at the other finer points of the Core architecture.
Time for some jargon
Here are the five important features that were showcased by Intel during one of their recent Intel Developer Forums: (a)Intel Wide Dynamic Execution
(b)Intel Advanced Smart cache
(c)Intel Intelligent power capability
(d)Intel Advanced Digital media boost
(e)Intel Smart Memory Access
Intel Wide Dynamic Execution:
With the Wide Dynamic Execution, the two cores in the processor are individually capable of executing up to four instructions per clock cycle. That’s a 33 percent improvement over the earlier Intel cores which could execute three instructions per clock. This basically means that the Conroe is able to process more instructions per clock cycle, thus allowing for faster execution time.
Micro and Macro Fusion:
Intel has included the short pipeline design into the Conroe. The shorter pipeline consists of only 14 stages compared to the 30+ stages in the Pressler core, thus reducing the penalty caused due to wrongly predicted data while it was being fetched in advance. The micro and macro fusion capabilities further increase the performance of the Conroe. The macro fusion feature combines two instructions called the compare and jump. This facilitates the execution of two instructions in a time frame that can only execute a single instruction. This feature increases the performance of applications with multiple compare and jump instructions.
Intel Advanced Smart Cache
The Core 2 Duo packs in two cores onto the single 65 nm die. The two cores share a massive 4 MB cache (2 MB in case of the E6300 and the E6400). The increased cache leads to quicker access of frequently used data as the processor does not need to search for the data in the main memory. Besides, access to L2 cache is much faster then access to the physical memory. In the Pentium D the caches are independent to each core. Using a single L2 cache lets each core utilize the L2 cache depending on its requirements and hence simplifies cache coherence. Cache coherence is intended to manage conflicts and maintain consistency between cache and memory. But there are disadvantages of sharing the L2 cache. If both the cores are running heavy applications that access huge amount of system memory, they could repeatedly strike the whole cache, thus reducing its effectiveness.
Intel Intelligent Power Capability
The Conroe processor is capable of switching off/deactivating certain parts of the processor and the cache without causing any loss in performance. This performance on demand technology ensures quick system response while drastically reducing the power required to run the processor.
Intel Advanced Digital Media Boost
This feature significantly improves performance when executing streaming instructions like SSE, SSE2 and SSE3. The speed of execution of applications that frequently use these instructions like video, speech, image processing, encryption, engineering and scientific applications, is increased dramatically as it allows 128-bit instructions to be completely executed at a throughput rate of one per clock cycle, effectively doubling the speed of execution as compared to previous generation processorsIntel Smart Memory Access
This feature helps in accelerating out-of-order execution by optimizing the use of data bandwidth from the memory subsystem. A newly designed prediction mechanism reduces the time for which an instruction has to wait for data to arrive. The data is moved to the faster L2 cache before execution, thus keeping the road from memory to the CPU occupied eventually increasing data throughput and system performance. It is clear that Intel has incorporated several performance enhancing changes in the Conroe processor’s DNA. Read on to find out if these performance enhancing features are reflected in our synthetic and real world benchmarks.
Although we would have ideally liked to compare the Conroe against the FX-62, we could not do so because we did not receive the processors simultaneously. That is why we have stacked up the Conroe against the Pentium D 930 instead of the Athlon 64 FX-62. Let us put all the speculation aside and see whether Intel really has a winner in hand.
SiSoft Sandra (Processor and Memory Bandwidth)
SiSoft Sandra processor benchmark shows a considerable increase in performance in both the Dhrystone ALU benchmark and the iSSE3 Whetstone benchmark. The memory bandwidth benchmark is the only place where the E6700 falls behind. An important reason why the FX-62 has greater bandwidth is because the latencies are greatly reduced. This is a direct result of the onboard memory controller.
Our PC Mark 2005 test suite confirmed that the Conroe is indeed the fastest processor around with the score crossing the 7600 mark.
As is the case with more and more new games today, at higher resolutions, they become increasingly GPU dependent. Its also evident in the case of Doom 3 as you see frames almost leveling at 1600x1200 with full details enabled. It would be worth investing in a high-end graphics solution to play games at higher resolutions rather than investing in a faster CPU.
Real world tests
The Conroe is about twice as fast as its previous generation counterpart. As we can see from the results, both its cores share the load seamlessly during multiprocessing without a degradation in performance.
The socket for Conroe still remains the same i.e. LGA 775 but it works only on the newer 965P and 975X chipsets. We used Biostar’s TForce P965 Deluxe board, which uses the 965P chipset for benchmarking. Along with that we used Kingston’s 1 GB kit DDR2 1066 MHz Non-ECC CL5 (kit of 2x512 MB). At default speeds, the board under-clocked it to 800 MHz with a timing of 5-5-5-16. Conroe compatible boards with chipsets from Nvidia and ATI are also available. (The Radeon Xpress 200 chipset from ATI and the nForce 570 and 590 SLI from Nvidia support the Conroe.)
How to upgrade to Conroe
With the ASRock 775Twins 2.0 motherboard, which is based on ATI Radeon Xpress 200 chipset, you can use your existing DDR RAM as it supports both DDR and DDR2 RAM and the board costs a mere Rs 3,500. You can get the E6300 for a sum of Rs 9,700 and you are ready to roll.
Intel has certainly made a smashing comeback with the Conroe. It breaks all performance records compared to its predecessors as well as offerings provided by its competition. Although we did not get the opportunity to do a direct comparision of the Conroe with the FX-62, from what we have seen, it pretty much thrashes its AMD counterpart in almost all benchmarks. Conroe is definitely jackpot material. At a price point of Rs 27,500, it provides better value for money compared to the Athlon 64 FX-62 and is definitely the processor to consider if you are buying a new system or looking for an upgrade.