Samsung Electronics says it will report a record quarterly operating profit of 8.1tn Korean won (£4.5bn), nearly double last year's and up 25% sequentially, as strong sales of high-end TVs and Galaxy smartphones more than offset reduced orders for chips and screens from Apple, its main rival and leading customer.

The figure covers the three months to the end of September. Most analysts, however, expect its run of four straight record quarters to end in December as the South Korean group, the world's leading maker of smartphones, TVs and memory chips, ramps up its marketing to counter Apple's new iPhone and other products in the increasingly crowded and competitive $200bn (£123.5bn) global smartphone market.

The operating profit figure is an estimate provided by Samsung itself in an earnings preview. That beat the consensus from a poll of 26 analysts, who pegged it at 7.6tn won, up from 4.25tn a year ago.

Samsung may have spent around $2.7bn on marketing in July-September alone around the London Olympic Games, for which it was a major sponsor, and new Galaxy promotions, Credit Suisse has estimated.

This year's expected record profit of 28tn won will also trigger higher performance-related payouts to many of Samsung's 206,000 staff early next year. The business may have to set money aside in the current quarter if it fails in an appeal to overturn a US court verdict from August which awarded more than $1bn in damages to Apple for patent infringements on phones and tablets.

"Fourth-quarter profit will be pressured by one-off expenses: performance payouts and some $1bn in legal provisioning relating to the Apple litigation. Excluding those, core earnings will remain solid and a swing factor is how much Samsung spends on marketing," said Lee Sun-tae, analyst at NH Investment & Securities.

Analysts expect earnings to decline until the second quarter of next year as a slump in computer sales and a weak global economy sap demand for chips and electronics products.

Smartphone tightrope

"The biggest risk for Samsung is competitive product line-ups from its rivals such as the iPhone 5. Because handsets drive most of its profits, one misstep in handsets could result in losses for the whole Samsung group," said Byun Han-joon, an analyst at KB Investment & Securities.

So far though, there is no sign of that happening, with its former key rivals – Finland's Nokia, Taiwan's HTC and Motorola in the US – falling behind in both profits and shipments.

Profit at Samsung's mobile division is likely to have more than doubled in July-September to around 5tn won – around two thirds of total group profit – as smartphone shipments are estimated to have topped 58m, including up to 20m Galaxy S IIIs. Samsung does not give figures for its shipments of smartphones, mobile phones or tablets, which are instead estimated by analysts.

The company, valued at around $197bn, estimated its third-quarter revenue at 52tn won, in line with forecasts.

Chips, cheaply?

Strong handset sales compensated for reduced profits from its chip business, as prices of its mainstay dynamic random access memory (DRAM) chips, used in computers and mobiles, dropped 14% in the September quarter. DRAM chips now trade below what it costs most contract manufacturers to make them, and will squeeze near-term earnings, analysts say.

Tablets and smartphones, the real growth areas, use far less storage. Samsung is expected to invest less in chips next year due to the drop in demand, which could be bad news for semiconductor equipment manufacturers such as ASML.

Kwon Oh-hyun, promoted to Samsung CEO in June, said late last month that the group has yet to finalise its 2013 investment plans.

Samsung is beefing up its product line-up, with the latest phone-cum-tablet Galaxy Note expected to go on sale in the US this month, and its ATIV smartphones that run on Microsoft's new Windows system to compete with Nokia's Lumia series.

Note-taking

Samsung's mobile division chief, JK Shin last, week predicted that sales of its large-screen Galaxy Note II could be three times higher than those of its predecessor model in the three months after launch. That would suggest sales of around 10m devices by the end of this year.

Some analysts see the Note II, along with a stripped-down, cheaper version of the flagship Galaxy S III smartphone and rising NAND flash memory chip prices helping Samsung deliver higher fourth-quarter profit. Nomura on Friday predicted October-December profit could be up to 10% more than the 8.1tn won in July-September.

In a note on Friday, Citi analyst Henry Kim predicted strong October-December profits, driven by a recovery in semiconductors, though telecoms operating margins could decline by 5 percentage points to 15% as it spends more on marketing. "The semiconductor division will show the strongest momentum," he said.

Despite a bruising series of patent disputes and the reputational risk of the US court defeat in August, Samsung's brand value has surged this year as it shipped more handsets and smartphones than any of its rivals. The value of the Samsung brand has jumped to 9th in the world – up from 17th last year – at $32.9bn, according to brand consultancy Interbrand. That's more than Toyota Motor, but less than half of second-ranked Apple's $76.6bn.