Xiaomi Mi 4i review: Hands down

Performance

The Xiaomi Mi 4i is no powerhouse and its specs shout mid-range all-around, but it packs a high-res 1080p display, which may be a bit too taxing on the GPU. The Mi 4i is powered by a Qualcomm Snapdragon 615 SoC, which was created for the mid-range market. It consists of a total of eight Cortex A53 cores, four clocked at 1.7 GHz and the other four at 1.1 GHz. The GPU in charge of graphics is Adreno 405, which isn't very impressive, especially running at Full HD. Finally, there is 2GB of RAM.

Xiaomi pushed a major firmware update already, which should be fixing the widespread overheating issues. Indeed we tested the device before the update and it got so hot under CPU pressure that we became concerned for its well-being. The update tunes down the processor, when it reaches a temperature threshold and prevents the device for getting too hot. The Mi 4i still gets really warm, but now we are not afraid it will catch fire in our hands.

It seems the latest generation Snapdragon chips are plagued by overheating issues and the only solutions is CPU throttling. While the 8-core CPU seems like a great on paper, especially with the high core clocks in the Mi 4i, it can only be unleashed to show its full potential for very short time periods.

We ran GeekBench 3 CPU test before and after the firmware update and we found out a firm 15% drop in the score. The Mi 4i still does OK - it offers almost the same CPU performance as other Snapdragon 615 devices (Sony Xperia M4 Aqua, Oppo R1x, HTC Desire 820). Yet four Krait 400 within the Xiaomi Mi 4 (Snapdragon 801) still do better than those 8 Cortex-A53 cores in the Mi 4i.

GeekBench 3

Higher is better

• Lenovo Vibe X2
  3647
• Xiaomi Mi 4
  3175
• Sony Xperia Z1 Compact
  2968
• Samsung Galaxy A7 (S615)
  2880
• Oppo R5
  2806
• HTC Desire 820
  2586
• Oppo R1x
  2507
• Sony Xperia M4 Aqua
  2375
• Xiaomi Mi 4i
  2336
• Samsung Galaxy E7
  1468

The compound AnTuTu puts the Xiaomi Mi 4i once again very closely to the rest of the Snapdragon 615 gang, though beating it by a hair.

AnTuTu 5

Higher is better

• Lenovo Vibe X2
  46666
• Xiaomi Mi 4i
  34491
• Sony Xperia M4 Aqua
  32217
• Samsung Galaxy A7 (S615)
  31436
• Oppo R5
  31417
• Oppo R1x
  30187
• HTC Desire 820
  27070
• Samsung Galaxy E7
  21562

Another compound benchmark we ran was the Basemark OS II. The Mi 4i did fine here, scoring the same as its chipset stablemates. The Sony M4 Aqua did slightly better, but it has the advantage of lower-res display.

Basemark OS II

Higher is better

• Xiaomi Mi 4
  1324
• Lenovo Vibe X2
  930
• Sony Xperia M4 Aqua
  883
• Xiaomi Mi 4i
  843
• Samsung Galaxy A7 (S615)
  786
• Oppo R5
  772
• Oppo R1x
  745
• HTC Desire 820
  725
• Samsung Galaxy E7
  600

The Cortex-A53 per-core performance is similar to others available in this price range, beaten only by the faster Krait (Mi 4, Xperia Z1 Compact) and Cortex-A17 (Vibe X2). The multi-core score is rather disappointing though.

Basemark OS II (single-core)

Higher is better

• Xiaomi Mi 4
  2573
• Lenovo Vibe X2
  2571
• HTC Desire 820
  1812
• Oppo R1x
  1664
• Oppo R5
  1657
• Xiaomi Mi 4i
  1651
• Samsung Galaxy A7 (S615)
  1572
• Samsung Galaxy E7
  1514
• Sony Xperia M4 Aqua
  1453

Basemark OS II (multi-core)

Higher is better

• Lenovo Vibe X2
  13999
• Oppo R5
  10000
• Xiaomi Mi 4
  9508
• Samsung Galaxy A7 (S615)
  9284
• Sony Xperia M4 Aqua
  8592
• HTC Desire 820
  8453
• Xiaomi Mi 4i
  7749
• Oppo R1x
  7508
• Samsung Galaxy E7
  6172

GPU tests confirmed our suspicions - Adreno 405 is not cut out for high-end gaming on a 1080p screen. Here the Adreno 330 GPU performs twice as well. Look at the 1080p onscreen tests as the Sony Xperia M4 Aqua has a 720p screen, while the Xiaomi Mi 4i needs to render at 1080p natively.

GFX 2.7 T-Rex (1080p offscreen)

Higher is better

• Xiaomi Mi 4
  27.6
• Sony Xperia Z1 Compact
  22
• Lenovo Vibe X2
  17.8
• Samsung Galaxy S4 Octa
  17.1
• Oppo R5
  15.1
• Samsung Galaxy A7 (S615)
  15
• HTC Desire 820
  15
• Sony Xperia M4 Aqua
  14.9
• Xiaomi Mi 4i
  14
• Oppo R1x
  12
• Samsung Galaxy E7
  5.3

GFX 3.0 Manhattan (1080p offscreen)

Higher is better

• Xiaomi Mi 4
  11.6
• Sony Xperia Z1 Compact
  9
• Xiaomi Mi 4i
  6.2
• Lenovo Vibe X2
  6.1
• Sony Xperia M4 Aqua
  5.84
• Samsung Galaxy A7 (S615)
  5.8
• Oppo R5
  5.8
• HTC Desire 820
  5.7
• Oppo R1x
  4.9
• Samsung Galaxy E7
  1.8

GFX 2.7 T-Rex (onscreen)

Higher is better

• Sony Xperia Z1 Compact
  34
• Xiaomi Mi 4
  28.2
• HTC Desire 820
  26
• Sony Xperia M4 Aqua
  25.8
• Oppo R1x
  20
• Lenovo Vibe X2
  17
• Samsung Galaxy A7 (S615)
  15
• Oppo R5
  14.8
• Xiaomi Mi 4i
  14
• Samsung Galaxy E7
  9.6

GFX 3.0 Manhattan (onscreen)

Higher is better

• Sony Xperia Z1 Compact
  17
• Sony Xperia M4 Aqua
  12.2
• HTC Desire 820
  12
• Xiaomi Mi 4
  11.3
• Oppo R1x
  9.6
• Xiaomi Mi 4i
  6.2
• Lenovo Vibe X2
  6.1
• Samsung Galaxy A7 (S615)
  5.8
• Oppo R5
  5.8
• Samsung Galaxy E7
  3.9

The Basemark X GPU tests gauges only the offscreen performance, where the Adreno 405 in the Xiaomi Mi 4i isn't at disadvantage. The competitors are not doing much better here.

Basemark X

Higher is better

• Lenovo Vibe X2
  6512
• Sony Xperia M4 Aqua
  5105
• Xiaomi Mi 4i
  4875
• HTC Desire 820
  4859
• Oppo R5
  4855
• Samsung Galaxy A7 (S615)
  4802
• Oppo R1x
  4018
• Samsung Galaxy E7
  1915

Moving on to web browsing tests, JavaScript performance is not spectacular, but it's OK.

Kraken 1.1

Lower is better

• Lenovo Vibe X2
  4747
• Xiaomi Mi 4
  6137
• Xiaomi Mi 4i
  11439
• Oppo R5
  11656
• Samsung Galaxy A7 (S615)
  12266
• Oppo R1x
  12826
• Samsung Galaxy E7
  13462
• HTC Desire 820
  13568
• Sony Xperia M4 Aqua
  13609

Still, general browsing the web is generally smooth and fast as BrowserMark 2.1 confirms. It puts the Mi 4i above a good number of quite powerful devices.

BrowserMark 2.1

Higher is better

• Lenovo Vibe X2
  2211
• Samsung Galaxy A7 (S615)
  1655
• Xiaomi Mi 4i
  1396
• Samsung Galaxy E7
  1344
• Oppo R5
  1319
• Sony Xperia M4 Aqua
  1171
• HTC Desire 820
  991
• Xiaomi Mi 4
  744
• Oppo R1x
  627

The Mi 4i handles processor intensive apps well, though it does get rather warm. However for gaming we'd look for an alternative - the Adreno 405 is just not up to the 1080p task. The web browsing experience is solid, while the overall Android+MIUI experience is very smooth.