When the Galaxy S4 was announced many months ago, Samsung was sure to point out that there would be two major variants which is usually the case for most flagship phone launches. Such decisions are definitely not made to incite confusion with consumers, but end up being necessary to cater to the entire globe in which different countries and carriers utilize different cellular technology for their networks. In the case of the Galaxy S4, things go a little bit deeper than separate radios (GSM and CDMA) and the internals of both the i9500 and i9505 variants are drastically different. On the outside, however, they remain identical which is a feat in itself considering the internal makeup.
The processor is the brains of most devices, and the Galaxy S4 is no exception. The processors used for each variant is also one of the hottest topics of discussion when speaking about the differences between the i9500 and i9505. Samsung made a splash when they announced the Exynos 5 with an octa-core processor which means eight cores in a single CPU. For the i9505, Samsung opted for a Snapdragon 600, which is a quad-core processor designed and manufactured by Qualcomm.
The octa-core Exynos 5 utilizes two quad-core clusters of processing power: a 1.6GHz Cortex-A15 and 1.2GHz Cortex-A7. The logic behind this design is for power savings, allowing the chipset to manage which chipsets to use when more power is needed and when not much power is necessary, allowing much more efficiency since eight cores can be a huge drain on the battery.
The quad-core Snapdragon 600 is clocked at 1.9GHz and also includes an Adreno 320 GPU as part of its chipset. Qualcomm has made a major push into selling their solutions as being a great solution for gaming and they have stiff competition in the market as nVidia makes their strong push into mobile with their Tegra chipsets.
So, is the octa-core that much better than the quad-core when the two variants are pitted against each other? Engadget ran a benchmark comparing the two in great detail, which you can find here. The verdict was marginal, to say the least. While the Exynos 5 did outperform the Snapdragon 600 in some tests, it was also bested in other and for all intents and purposes, they’re roughly equivalent. The difference in performance is probably less than expected when eyeballing a quad-core vs. octa-core benchmark, but there are reasons to it. The main reason is what we discussed a couple of paragraphs ago: the octa-core is comprised of two quad-core clusters for power savings as opposed to being a straightforward octa-core processing unit. Engadget also noticed that battery life on the Exynos 5 i9500 was less efficient than the quad-core i9505.
The main reason that two main variants of the Galaxy S4 is exist is networks. There are two cellular networks that essentially cover the entire world: GSM and CDMA. Most other cellular networks such as iDEN and TDMA are becoming obsolete, and some would argue that even CDMA is on the way out. GSM is by far the most prevalent network technology in the world, and if you’ve ever had a phone with a SIM card, chances are it was GSM with a few exceptions such as iDEN.
LTE, on the other hand, has seen an almost unanimous adoption as the preferred method of data telephony, and it is actually designed to co-exist with the existing voice telephony networks of GSM and CDMA. Eventually, LTE will be able to handle both voice and data, which will make devices even smaller in the future because multiple radios will no longer be needed. LTE is considered a 4G network technology, and most of the US carriers call their network 4G LTE which was at first used to differentiate themselves from Sprint’s 4G network, which was the first 4G network in the United States but utilized the dying WiMAX technology for data connectivity.
One of the most overlooked technical aspects in these network differentiations is frequencies. A GSM device will not necessarily be functional on any GSM network because it may operate on different bands, and this is another huge reason why two variants are pretty much necessary for any worldwide device.
The i9500 has no LTE radio in it, but does utilize DC-HSPA+ for data connectivity. The i9505 has LTE connectivity and also operates on the 2100MHz HSPA+ band utilized by US carriers AT&T and T-Mobile, but 4G LTE will not function in the United States because of frequency differences.
If you plan on using your unlocked Galaxy S4 in the United States, the i9505 with the quad-core chipset is going to work best. The i9500, with its octa-core processor, will still function in the United States but with lower data speeds.
There is no unlocked CDMA Galaxy S4 devices because of the nature of the network, so an unlocked Galaxy S4 will not work on Sprint or Verizon in the United States, nor any other CDMA carrier. These companies purchase their own branded devices in bulk and sell them to their own customers once they’ve inputted the serial numbers into their system, allowing them to be activated on their networks. If you were to come across a CDMA Galaxy S4, it will only activate on the carrier which initially sold it unless you’re friends with someone who can add the serial number into the company’s database, which is tough.
Everything else between the two variants is essentially identical. The housing is exactly the same, as is the color selection (for now). The batteries are both rated at 2,600mAh and they’re all available in 16GB, 32GB, and 64GB storage capacities. Both variants also take SIM cards, which is something the CDMA models will not because of the network architecture. All Galaxy S4 accessories and cases will definitely work with both variants as well.
Weight is also identical between the two as well, weighing in a 4.6oz or 130 grams. Both are equipped with 2GB of RAM as well.
The GPU’s on board are slightly different, with the i9500 utilizing a PowerVR SGX544MP3 with three cores, and the i9505 sporting the Adreno 320 which is bested only by some high-end Apple iOS products.